Eric Lee / smarc-ti-linux-kernel

1

/*

1

/*

2

* linux/kernel/exit.c

2

* linux/kernel/exit.c

3

*

3

*

4

5

*/

5

*/

6

7

#include <linux/mm.h>

7

#include <linux/mm.h>

8

#include <linux/slab.h>

8

#include <linux/slab.h>

9

#include <linux/interrupt.h>

9

#include <linux/interrupt.h>

10

#include <linux/module.h>

10

#include <linux/module.h>

11

#include <linux/capability.h>

11

#include <linux/capability.h>

12

#include <linux/completion.h>

12

#include <linux/completion.h>

13

#include <linux/personality.h>

13

#include <linux/personality.h>

14

#include <linux/tty.h>

14

#include <linux/tty.h>

15

#include <linux/iocontext.h>

15

#include <linux/iocontext.h>

16

#include <linux/key.h>

16

#include <linux/key.h>

17

#include <linux/security.h>

17

#include <linux/security.h>

18

#include <linux/cpu.h>

18

#include <linux/cpu.h>

19

#include <linux/acct.h>

19

#include <linux/acct.h>

20

#include <linux/tsacct_kern.h>

20

#include <linux/tsacct_kern.h>

21

#include <linux/file.h>

21

#include <linux/file.h>

22

#include <linux/fdtable.h>

22

#include <linux/fdtable.h>

23

#include <linux/freezer.h>

23

#include <linux/freezer.h>

24

#include <linux/binfmts.h>

24

#include <linux/binfmts.h>

25

#include <linux/nsproxy.h>

25

#include <linux/nsproxy.h>

26

#include <linux/pid_namespace.h>

26

#include <linux/pid_namespace.h>

27

#include <linux/ptrace.h>

27

#include <linux/ptrace.h>

28

#include <linux/profile.h>

28

#include <linux/profile.h>

29

#include <linux/mount.h>

29

#include <linux/mount.h>

30

#include <linux/proc_fs.h>

30

#include <linux/proc_fs.h>

31

#include <linux/kthread.h>

31

#include <linux/kthread.h>

32

#include <linux/mempolicy.h>

32

#include <linux/mempolicy.h>

33

#include <linux/taskstats_kern.h>

33

#include <linux/taskstats_kern.h>

34

#include <linux/delayacct.h>

34

#include <linux/delayacct.h>

35

#include <linux/cgroup.h>

35

#include <linux/cgroup.h>

36

#include <linux/syscalls.h>

36

#include <linux/syscalls.h>

37

#include <linux/signal.h>

37

#include <linux/signal.h>

38

#include <linux/posix-timers.h>

38

#include <linux/posix-timers.h>

39

#include <linux/cn_proc.h>

39

#include <linux/cn_proc.h>

40

#include <linux/mutex.h>

40

#include <linux/mutex.h>

41

#include <linux/futex.h>

41

#include <linux/futex.h>

42

#include <linux/pipe_fs_i.h>

42

#include <linux/pipe_fs_i.h>

43

#include <linux/audit.h> /* for audit_free() */

43

#include <linux/audit.h> /* for audit_free() */

44

#include <linux/resource.h>

44

#include <linux/resource.h>

45

#include <linux/blkdev.h>

45

#include <linux/blkdev.h>

46

#include <linux/task_io_accounting_ops.h>

46

#include <linux/task_io_accounting_ops.h>

47

#include <linux/tracehook.h>

47

#include <linux/tracehook.h>

48

#include <linux/fs_struct.h>

48

#include <linux/fs_struct.h>

49

#include <linux/init_task.h>

49

#include <linux/init_task.h>

50

#include <linux/perf_event.h>

50

#include <linux/perf_event.h>

51

#include <trace/events/sched.h>

51

#include <trace/events/sched.h>

52

#include <linux/hw_breakpoint.h>

52

#include <linux/hw_breakpoint.h>

53

#include <linux/oom.h>

53

#include <linux/oom.h>

54

#include <linux/writeback.h>

54

#include <linux/writeback.h>

55

#include <linux/shm.h>

55

#include <linux/shm.h>

56

57

#include <asm/uaccess.h>

57

#include <asm/uaccess.h>

58

#include <asm/unistd.h>

58

#include <asm/unistd.h>

59

#include <asm/pgtable.h>

59

#include <asm/pgtable.h>

60

#include <asm/mmu_context.h>

60

#include <asm/mmu_context.h>

61

62

static void exit_mm(struct task_struct * tsk);

62

static void exit_mm(struct task_struct * tsk);

63

64

static void __unhash_process(struct task_struct *p, bool group_dead)

64

static void __unhash_process(struct task_struct *p, bool group_dead)

65

{

65

{

66

nr_threads--;

66

nr_threads--;

67

detach_pid(p, PIDTYPE_PID);

67

detach_pid(p, PIDTYPE_PID);

68

if (group_dead) {

68

if (group_dead) {

69

detach_pid(p, PIDTYPE_PGID);

69

detach_pid(p, PIDTYPE_PGID);

70

detach_pid(p, PIDTYPE_SID);

70

detach_pid(p, PIDTYPE_SID);

71

72

list_del_rcu(&p->tasks);

72

list_del_rcu(&p->tasks);

73

list_del_init(&p->sibling);

73

list_del_init(&p->sibling);

74

__this_cpu_dec(process_counts);

74

__this_cpu_dec(process_counts);

75

}

75

}

76

list_del_rcu(&p->thread_group);

76

list_del_rcu(&p->thread_group);

77

list_del_rcu(&p->thread_node);

77

list_del_rcu(&p->thread_node);

78

}

78

}

79

80

/*

80

/*

81

* This function expects the tasklist_lock write-locked.

81

* This function expects the tasklist_lock write-locked.

82

*/

82

*/

83

static void __exit_signal(struct task_struct *tsk)

83

static void __exit_signal(struct task_struct *tsk)

84

{

84

{

85

struct signal_struct *sig = tsk->signal;

85

struct signal_struct *sig = tsk->signal;

86

bool group_dead = thread_group_leader(tsk);

86

bool group_dead = thread_group_leader(tsk);

87

struct sighand_struct *sighand;

87

struct sighand_struct *sighand;

88

struct tty_struct *uninitialized_var(tty);

88

struct tty_struct *uninitialized_var(tty);

89

cputime_t utime, stime;

89

cputime_t utime, stime;

90

91

sighand = rcu_dereference_check(tsk->sighand,

91

sighand = rcu_dereference_check(tsk->sighand,

92

lockdep_tasklist_lock_is_held());

92

lockdep_tasklist_lock_is_held());

93

spin_lock(&sighand->siglock);

93

spin_lock(&sighand->siglock);

94

95

posix_cpu_timers_exit(tsk);

95

posix_cpu_timers_exit(tsk);

96

if (group_dead) {

96

if (group_dead) {

97

posix_cpu_timers_exit_group(tsk);

97

posix_cpu_timers_exit_group(tsk);

98

tty = sig->tty;

98

tty = sig->tty;

99

sig->tty = NULL;

99

sig->tty = NULL;

100

} else {

100

} else {

101

/*

101

/*

102

* This can only happen if the caller is de_thread().

102

* This can only happen if the caller is de_thread().

103

* FIXME: this is the temporary hack, we should teach

103

* FIXME: this is the temporary hack, we should teach

104

* posix-cpu-timers to handle this case correctly.

104

* posix-cpu-timers to handle this case correctly.

105

*/

105

*/

106

if (unlikely(has_group_leader_pid(tsk)))

106

if (unlikely(has_group_leader_pid(tsk)))

107

posix_cpu_timers_exit_group(tsk);

107

posix_cpu_timers_exit_group(tsk);

108

109

/*

109

/*

110

* If there is any task waiting for the group exit

110

* If there is any task waiting for the group exit

111

* then notify it:

111

* then notify it:

112

*/

112

*/

113

if (sig->notify_count > 0 && !--sig->notify_count)

113

if (sig->notify_count > 0 && !--sig->notify_count)

114

wake_up_process(sig->group_exit_task);

114

wake_up_process(sig->group_exit_task);

115

116

if (tsk == sig->curr_target)

116

if (tsk == sig->curr_target)

117

sig->curr_target = next_thread(tsk);

117

sig->curr_target = next_thread(tsk);

118

/*

118

/*

119

* Accumulate here the counters for all threads but the

119

* Accumulate here the counters for all threads but the

120

* group leader as they die, so they can be added into

120

* group leader as they die, so they can be added into

121

* the process-wide totals when those are taken.

121

* the process-wide totals when those are taken.

122

* The group leader stays around as a zombie as long

122

* The group leader stays around as a zombie as long

123

* as there are other threads. When it gets reaped,

123

* as there are other threads. When it gets reaped,

124

* the exit.c code will add its counts into these totals.

124

* the exit.c code will add its counts into these totals.

125

* We won't ever get here for the group leader, since it

125

* We won't ever get here for the group leader, since it

126

* will have been the last reference on the signal_struct.

126

* will have been the last reference on the signal_struct.

127

*/

127

*/

128

task_cputime(tsk, &utime, &stime);

128

task_cputime(tsk, &utime, &stime);

129

sig->utime += utime;

129

sig->utime += utime;

130

sig->stime += stime;

130

sig->stime += stime;

131

sig->gtime += task_gtime(tsk);

131

sig->gtime += task_gtime(tsk);

132

sig->min_flt += tsk->min_flt;

132

sig->min_flt += tsk->min_flt;

133

sig->maj_flt += tsk->maj_flt;

133

sig->maj_flt += tsk->maj_flt;

134

sig->nvcsw += tsk->nvcsw;

134

sig->nvcsw += tsk->nvcsw;

135

sig->nivcsw += tsk->nivcsw;

135

sig->nivcsw += tsk->nivcsw;

136

sig->inblock += task_io_get_inblock(tsk);

136

sig->inblock += task_io_get_inblock(tsk);

137

sig->oublock += task_io_get_oublock(tsk);

137

sig->oublock += task_io_get_oublock(tsk);

138

task_io_accounting_add(&sig->ioac, &tsk->ioac);

138

task_io_accounting_add(&sig->ioac, &tsk->ioac);

139

sig->sum_sched_runtime += tsk->se.sum_exec_runtime;

139

sig->sum_sched_runtime += tsk->se.sum_exec_runtime;

140

}

140

}

141

142

sig->nr_threads--;

142

sig->nr_threads--;

143

__unhash_process(tsk, group_dead);

143

__unhash_process(tsk, group_dead);

144

145

/*

145

/*

146

* Do this under ->siglock, we can race with another thread

146

* Do this under ->siglock, we can race with another thread

147

* doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.

147

* doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.

148

*/

148

*/

149

flush_sigqueue(&tsk->pending);

149

flush_sigqueue(&tsk->pending);

150

tsk->sighand = NULL;

150

tsk->sighand = NULL;

151

spin_unlock(&sighand->siglock);

151

spin_unlock(&sighand->siglock);

152

153

__cleanup_sighand(sighand);

153

__cleanup_sighand(sighand);

154

clear_tsk_thread_flag(tsk,TIF_SIGPENDING);

154

clear_tsk_thread_flag(tsk,TIF_SIGPENDING);

155

if (group_dead) {

155

if (group_dead) {

156

flush_sigqueue(&sig->shared_pending);

156

flush_sigqueue(&sig->shared_pending);

157

tty_kref_put(tty);

157

tty_kref_put(tty);

158

}

158

}

159

}

159

}

160

161

static void delayed_put_task_struct(struct rcu_head *rhp)

161

static void delayed_put_task_struct(struct rcu_head *rhp)

162

{

162

{

163

struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);

163

struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);

164

165

perf_event_delayed_put(tsk);

165

perf_event_delayed_put(tsk);

166

trace_sched_process_free(tsk);

166

trace_sched_process_free(tsk);

167

put_task_struct(tsk);

167

put_task_struct(tsk);

168

}

168

}

169

170

171

void release_task(struct task_struct * p)

171

void release_task(struct task_struct * p)

172

{

172

{

173

struct task_struct *leader;

173

struct task_struct *leader;

174

int zap_leader;

174

int zap_leader;

175

repeat:

175

repeat:

176

/* don't need to get the RCU readlock here - the process is dead and

176

/* don't need to get the RCU readlock here - the process is dead and

177

* can't be modifying its own credentials. But shut RCU-lockdep up */

177

* can't be modifying its own credentials. But shut RCU-lockdep up */

178

rcu_read_lock();

178

rcu_read_lock();

179

atomic_dec(&__task_cred(p)->user->processes);

179

atomic_dec(&__task_cred(p)->user->processes);

180

rcu_read_unlock();

180

rcu_read_unlock();

181

182

proc_flush_task(p);

182

proc_flush_task(p);

183

184

write_lock_irq(&tasklist_lock);

184

write_lock_irq(&tasklist_lock);

185

ptrace_release_task(p);

185

ptrace_release_task(p);

186

__exit_signal(p);

186

__exit_signal(p);

187

188

/*

188

/*

189

* If we are the last non-leader member of the thread

189

* If we are the last non-leader member of the thread

190

* group, and the leader is zombie, then notify the

190

* group, and the leader is zombie, then notify the

191

* group leader's parent process. (if it wants notification.)

191

* group leader's parent process. (if it wants notification.)

192

*/

192

*/

193

zap_leader = 0;

193

zap_leader = 0;

194

leader = p->group_leader;

194

leader = p->group_leader;

195

if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {

195

if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {

196

/*

196

/*

197

* If we were the last child thread and the leader has

197

* If we were the last child thread and the leader has

198

* exited already, and the leader's parent ignores SIGCHLD,

198

* exited already, and the leader's parent ignores SIGCHLD,

199

* then we are the one who should release the leader.

199

* then we are the one who should release the leader.

200

*/

200

*/

201

zap_leader = do_notify_parent(leader, leader->exit_signal);

201

zap_leader = do_notify_parent(leader, leader->exit_signal);

202

if (zap_leader)

202

if (zap_leader)

203

leader->exit_state = EXIT_DEAD;

203

leader->exit_state = EXIT_DEAD;

204

}

204

}

205

206

write_unlock_irq(&tasklist_lock);

206

write_unlock_irq(&tasklist_lock);

207

release_thread(p);

207

release_thread(p);

208

call_rcu(&p->rcu, delayed_put_task_struct);

208

call_rcu(&p->rcu, delayed_put_task_struct);

209

210

p = leader;

210

p = leader;

211

if (unlikely(zap_leader))

211

if (unlikely(zap_leader))

212

goto repeat;

212

goto repeat;

213

}

213

}

214

215

/*

215

/*

216

* This checks not only the pgrp, but falls back on the pid if no

216

* This checks not only the pgrp, but falls back on the pid if no

217

* satisfactory pgrp is found. I dunno - gdb doesn't work correctly

217

* satisfactory pgrp is found. I dunno - gdb doesn't work correctly

218

* without this...

218

* without this...

219

*

219

*

220

* The caller must hold rcu lock or the tasklist lock.

220

* The caller must hold rcu lock or the tasklist lock.

221

*/

221

*/

222

struct pid *session_of_pgrp(struct pid *pgrp)

222

struct pid *session_of_pgrp(struct pid *pgrp)

223

{

223

{

224

struct task_struct *p;

224

struct task_struct *p;

225

struct pid *sid = NULL;

225

struct pid *sid = NULL;

226

227

p = pid_task(pgrp, PIDTYPE_PGID);

227

p = pid_task(pgrp, PIDTYPE_PGID);

228

if (p == NULL)

228

if (p == NULL)

229

p = pid_task(pgrp, PIDTYPE_PID);

229

p = pid_task(pgrp, PIDTYPE_PID);

230

if (p != NULL)

230

if (p != NULL)

231

sid = task_session(p);

231

sid = task_session(p);

232

233

return sid;

233

return sid;

234

}

234

}

235

236

/*

236

/*

237

* Determine if a process group is "orphaned", according to the POSIX

237

* Determine if a process group is "orphaned", according to the POSIX

238

* definition in 2.2.2.52. Orphaned process groups are not to be affected

238

* definition in 2.2.2.52. Orphaned process groups are not to be affected

239

* by terminal-generated stop signals. Newly orphaned process groups are

239

* by terminal-generated stop signals. Newly orphaned process groups are

240

* to receive a SIGHUP and a SIGCONT.

240

* to receive a SIGHUP and a SIGCONT.

241

*

241

*

242

* "I ask you, have you ever known what it is to be an orphan?"

242

* "I ask you, have you ever known what it is to be an orphan?"

243

*/

243

*/

244

static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)

244

static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)

245

{

245

{

246

struct task_struct *p;

246

struct task_struct *p;

247

248

do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

248

do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

249

if ((p == ignored_task) ||

249

if ((p == ignored_task) ||

250

(p->exit_state && thread_group_empty(p)) ||

250

(p->exit_state && thread_group_empty(p)) ||

251

is_global_init(p->real_parent))

251

is_global_init(p->real_parent))

252

continue;

252

continue;

253

254

if (task_pgrp(p->real_parent) != pgrp &&

254

if (task_pgrp(p->real_parent) != pgrp &&

255

task_session(p->real_parent) == task_session(p))

255

task_session(p->real_parent) == task_session(p))

256

return 0;

256

return 0;

257

} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

257

} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

258

259

return 1;

259

return 1;

260

}

260

}

261

262

int is_current_pgrp_orphaned(void)

262

int is_current_pgrp_orphaned(void)

263

{

263

{

264

int retval;

264

int retval;

265

266

read_lock(&tasklist_lock);

266

read_lock(&tasklist_lock);

267

retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);

267

retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);

268

read_unlock(&tasklist_lock);

268

read_unlock(&tasklist_lock);

269

270

return retval;

270

return retval;

271

}

271

}

272

273

static bool has_stopped_jobs(struct pid *pgrp)

273

static bool has_stopped_jobs(struct pid *pgrp)

274

{

274

{

275

struct task_struct *p;

275

struct task_struct *p;

276

277

do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

277

do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

278

if (p->signal->flags & SIGNAL_STOP_STOPPED)

278

if (p->signal->flags & SIGNAL_STOP_STOPPED)

279

return true;

279

return true;

280

} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

280

} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

281

282

return false;

282

return false;

283

}

283

}

284

285

/*

285

/*

286

* Check to see if any process groups have become orphaned as

286

* Check to see if any process groups have become orphaned as

287

* a result of our exiting, and if they have any stopped jobs,

287

* a result of our exiting, and if they have any stopped jobs,

288

* send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)

288

* send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)

289

*/

289

*/

290

static void

290

static void

291

kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)

291

kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)

292

{

292

{

293

struct pid *pgrp = task_pgrp(tsk);

293

struct pid *pgrp = task_pgrp(tsk);

294

struct task_struct *ignored_task = tsk;

294

struct task_struct *ignored_task = tsk;

295

296

if (!parent)

296

if (!parent)

297

/* exit: our father is in a different pgrp than

297

/* exit: our father is in a different pgrp than

298

* we are and we were the only connection outside.

298

* we are and we were the only connection outside.

299

*/

299

*/

300

parent = tsk->real_parent;

300

parent = tsk->real_parent;

301

else

301

else

302

/* reparent: our child is in a different pgrp than

302

/* reparent: our child is in a different pgrp than

303

* we are, and it was the only connection outside.

303

* we are, and it was the only connection outside.

304

*/

304

*/

305

ignored_task = NULL;

305

ignored_task = NULL;

306

307

if (task_pgrp(parent) != pgrp &&

307

if (task_pgrp(parent) != pgrp &&

308

task_session(parent) == task_session(tsk) &&

308

task_session(parent) == task_session(tsk) &&

309

will_become_orphaned_pgrp(pgrp, ignored_task) &&

309

will_become_orphaned_pgrp(pgrp, ignored_task) &&

310

has_stopped_jobs(pgrp)) {

310

has_stopped_jobs(pgrp)) {

311

__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);

311

__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);

312

__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);

312

__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);

313

}

313

}

314

}

314

}

315

316

/*

316

/*

317

* Let kernel threads use this to say that they allow a certain signal.

317

* Let kernel threads use this to say that they allow a certain signal.

318

* Must not be used if kthread was cloned with CLONE_SIGHAND.

318

* Must not be used if kthread was cloned with CLONE_SIGHAND.

319

*/

319

*/

320

int allow_signal(int sig)

320

int allow_signal(int sig)

321

{

321

{

322

if (!valid_signal(sig) || sig < 1)

322

if (!valid_signal(sig) || sig < 1)

323

return -EINVAL;

323

return -EINVAL;

324

325

spin_lock_irq(&current->sighand->siglock);

325

spin_lock_irq(&current->sighand->siglock);

326

/* This is only needed for daemonize()'ed kthreads */

326

/* This is only needed for daemonize()'ed kthreads */

327

sigdelset(&current->blocked, sig);

327

sigdelset(&current->blocked, sig);

328

/*

328

/*

329

* Kernel threads handle their own signals. Let the signal code

329

* Kernel threads handle their own signals. Let the signal code

330

* know it'll be handled, so that they don't get converted to

330

* know it'll be handled, so that they don't get converted to

331

* SIGKILL or just silently dropped.

331

* SIGKILL or just silently dropped.

332

*/

332

*/

333

current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;

333

current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;

334

recalc_sigpending();

334

recalc_sigpending();

335

spin_unlock_irq(&current->sighand->siglock);

335

spin_unlock_irq(&current->sighand->siglock);

336

return 0;

336

return 0;

337

}

337

}

338

339

EXPORT_SYMBOL(allow_signal);

339

EXPORT_SYMBOL(allow_signal);

340

341

int disallow_signal(int sig)

341

int disallow_signal(int sig)

342

{

342

{

343

if (!valid_signal(sig) || sig < 1)

343

if (!valid_signal(sig) || sig < 1)

344

return -EINVAL;

344

return -EINVAL;

345

346

spin_lock_irq(&current->sighand->siglock);

346

spin_lock_irq(&current->sighand->siglock);

347

current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;

347

current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;

348

recalc_sigpending();

348

recalc_sigpending();

349

spin_unlock_irq(&current->sighand->siglock);

349

spin_unlock_irq(&current->sighand->siglock);

350

return 0;

350

return 0;

351

}

351

}

352

353

EXPORT_SYMBOL(disallow_signal);

353

EXPORT_SYMBOL(disallow_signal);

354

355

#ifdef CONFIG_MM_OWNER

355

#ifdef CONFIG_MM_OWNER

356

/*

356

/*

357

* A task is exiting. If it owned this mm, find a new owner for the mm.

357

* A task is exiting. If it owned this mm, find a new owner for the mm.

358

*/

358

*/

359

void mm_update_next_owner(struct mm_struct *mm)

359

void mm_update_next_owner(struct mm_struct *mm)

360

{

360

{

361

struct task_struct *c, *g, *p = current;

361

struct task_struct *c, *g, *p = current;

362

363

retry:

363

retry:

364

/*

364

/*

365

* If the exiting or execing task is not the owner, it's

365

* If the exiting or execing task is not the owner, it's

366

* someone else's problem.

366

* someone else's problem.

367

*/

367

*/

368

if (mm->owner != p)

368

if (mm->owner != p)

369

return;

369

return;

370

/*

370

/*

371

* The current owner is exiting/execing and there are no other

371

* The current owner is exiting/execing and there are no other

372

* candidates. Do not leave the mm pointing to a possibly

372

* candidates. Do not leave the mm pointing to a possibly

373

* freed task structure.

373

* freed task structure.

374

*/

374

*/

375

if (atomic_read(&mm->mm_users) <= 1) {

375

if (atomic_read(&mm->mm_users) <= 1) {

376

mm->owner = NULL;

376

mm->owner = NULL;

377

return;

377

return;

378

}

378

}

379

380

read_lock(&tasklist_lock);

380

read_lock(&tasklist_lock);

381

/*

381

/*

382

* Search in the children

382

* Search in the children

383

*/

383

*/

384

list_for_each_entry(c, &p->children, sibling) {

384

list_for_each_entry(c, &p->children, sibling) {

385

if (c->mm == mm)

385

if (c->mm == mm)

386

goto assign_new_owner;

386

goto assign_new_owner;

387

}

387

}

388

389

/*

389

/*

390

* Search in the siblings

390

* Search in the siblings

391

*/

391

*/

392

list_for_each_entry(c, &p->real_parent->children, sibling) {

392

list_for_each_entry(c, &p->real_parent->children, sibling) {

393

if (c->mm == mm)

393

if (c->mm == mm)

394

goto assign_new_owner;

394

goto assign_new_owner;

395

}

395

}

396

397

/*

397

/*

398

* Search through everything else. We should not get

398

* Search through everything else. We should not get

399

* here often

399

* here often

400

*/

400

*/

401

do_each_thread(g, c) {

401

do_each_thread(g, c) {

402

if (c->mm == mm)

402

if (c->mm == mm)

403

goto assign_new_owner;

403

goto assign_new_owner;

404

} while_each_thread(g, c);

404

} while_each_thread(g, c);

405

406

read_unlock(&tasklist_lock);

406

read_unlock(&tasklist_lock);

407

/*

407

/*

408

* We found no owner yet mm_users > 1: this implies that we are

408

* We found no owner yet mm_users > 1: this implies that we are

409

* most likely racing with swapoff (try_to_unuse()) or /proc or

409

* most likely racing with swapoff (try_to_unuse()) or /proc or

410

* ptrace or page migration (get_task_mm()). Mark owner as NULL.

410

* ptrace or page migration (get_task_mm()). Mark owner as NULL.

411

*/

411

*/

412

mm->owner = NULL;

412

mm->owner = NULL;

413

return;

413

return;

414

415

assign_new_owner:

415

assign_new_owner:

416

BUG_ON(c == p);

416

BUG_ON(c == p);

417

get_task_struct(c);

417

get_task_struct(c);

418

/*

418

/*

419

* The task_lock protects c->mm from changing.

419

* The task_lock protects c->mm from changing.

420

* We always want mm->owner->mm == mm

420

* We always want mm->owner->mm == mm

421

*/

421

*/

422

task_lock(c);

422

task_lock(c);

423

/*

423

/*

424

* Delay read_unlock() till we have the task_lock()

424

* Delay read_unlock() till we have the task_lock()

425

* to ensure that c does not slip away underneath us

425

* to ensure that c does not slip away underneath us

426

*/

426

*/

427

read_unlock(&tasklist_lock);

427

read_unlock(&tasklist_lock);

428

if (c->mm != mm) {

428

if (c->mm != mm) {

429

task_unlock(c);

429

task_unlock(c);

430

put_task_struct(c);

430

put_task_struct(c);

431

goto retry;

431

goto retry;

432

}

432

}

433

mm->owner = c;

433

mm->owner = c;

434

task_unlock(c);

434

task_unlock(c);

435

put_task_struct(c);

435

put_task_struct(c);

436

}

436

}

437

#endif /* CONFIG_MM_OWNER */

437

#endif /* CONFIG_MM_OWNER */

438

439

/*

439

/*

440

* Turn us into a lazy TLB process if we

440

* Turn us into a lazy TLB process if we

441

* aren't already..

441

* aren't already..

442

*/

442

*/

443

static void exit_mm(struct task_struct * tsk)

443

static void exit_mm(struct task_struct * tsk)

444

{

444

{

445

struct mm_struct *mm = tsk->mm;

445

struct mm_struct *mm = tsk->mm;

446

struct core_state *core_state;

446

struct core_state *core_state;

447

448

mm_release(tsk, mm);

448

mm_release(tsk, mm);

449

if (!mm)

449

if (!mm)

450

return;

450

return;

451

sync_mm_rss(mm);

451

sync_mm_rss(mm);

452

/*

452

/*

453

* Serialize with any possible pending coredump.

453

* Serialize with any possible pending coredump.

454

* We must hold mmap_sem around checking core_state

454

* We must hold mmap_sem around checking core_state

455

* and clearing tsk->mm. The core-inducing thread

455

* and clearing tsk->mm. The core-inducing thread

456

* will increment ->nr_threads for each thread in the

456

* will increment ->nr_threads for each thread in the

457

* group with ->mm != NULL.

457

* group with ->mm != NULL.

458

*/

458

*/

459

down_read(&mm->mmap_sem);

459

down_read(&mm->mmap_sem);

460

core_state = mm->core_state;

460

core_state = mm->core_state;

461

if (core_state) {

461

if (core_state) {

462

struct core_thread self;

462

struct core_thread self;

463

up_read(&mm->mmap_sem);

463

up_read(&mm->mmap_sem);

464

465

self.task = tsk;

465

self.task = tsk;

466

self.next = xchg(&core_state->dumper.next, &self);

466

self.next = xchg(&core_state->dumper.next, &self);

467

/*

467

/*

468

* Implies mb(), the result of xchg() must be visible

468

* Implies mb(), the result of xchg() must be visible

469

* to core_state->dumper.

469

* to core_state->dumper.

470

*/

470

*/

471

if (atomic_dec_and_test(&core_state->nr_threads))

471

if (atomic_dec_and_test(&core_state->nr_threads))

472

complete(&core_state->startup);

472

complete(&core_state->startup);

473

474

for (;;) {

474

for (;;) {

475

set_task_state(tsk, TASK_UNINTERRUPTIBLE);

475

set_task_state(tsk, TASK_UNINTERRUPTIBLE);

476

if (!self.task) /* see coredump_finish() */

476

if (!self.task) /* see coredump_finish() */

477

break;

477

break;

478

freezable_schedule();

478

freezable_schedule();

479

}

479

}

480

__set_task_state(tsk, TASK_RUNNING);

480

__set_task_state(tsk, TASK_RUNNING);

481

down_read(&mm->mmap_sem);

481

down_read(&mm->mmap_sem);

482

}

482

}

483

atomic_inc(&mm->mm_count);

483

atomic_inc(&mm->mm_count);

484

BUG_ON(mm != tsk->active_mm);

484

BUG_ON(mm != tsk->active_mm);

485

/* more a memory barrier than a real lock */

485

/* more a memory barrier than a real lock */

486

task_lock(tsk);

486

task_lock(tsk);

487

tsk->mm = NULL;

487

tsk->mm = NULL;

488

up_read(&mm->mmap_sem);

488

up_read(&mm->mmap_sem);

489

enter_lazy_tlb(mm, current);

489

enter_lazy_tlb(mm, current);

490

task_unlock(tsk);

490

task_unlock(tsk);

491

mm_update_next_owner(mm);

491

mm_update_next_owner(mm);

492

mmput(mm);

492

mmput(mm);

493

}

493

}

494

495

/*

495

/*

496

* When we die, we re-parent all our children, and try to:

496

* When we die, we re-parent all our children, and try to:

497

* 1. give them to another thread in our thread group, if such a member exists

497

* 1. give them to another thread in our thread group, if such a member exists

498

* 2. give it to the first ancestor process which prctl'd itself as a

498

* 2. give it to the first ancestor process which prctl'd itself as a

499

* child_subreaper for its children (like a service manager)

499

* child_subreaper for its children (like a service manager)

500

* 3. give it to the init process (PID 1) in our pid namespace

500

* 3. give it to the init process (PID 1) in our pid namespace

501

*/

501

*/

502

static struct task_struct *find_new_reaper(struct task_struct *father)

502

static struct task_struct *find_new_reaper(struct task_struct *father)

503

__releases(&tasklist_lock)

503

__releases(&tasklist_lock)

504

__acquires(&tasklist_lock)

504

__acquires(&tasklist_lock)

505

{

505

{

506

struct pid_namespace *pid_ns = task_active_pid_ns(father);

506

struct pid_namespace *pid_ns = task_active_pid_ns(father);

507

struct task_struct *thread;

507

struct task_struct *thread;

508

509

thread = father;

509

thread = father;

510

while_each_thread(father, thread) {

510

while_each_thread(father, thread) {

511

if (thread->flags & PF_EXITING)

511

if (thread->flags & PF_EXITING)

512

continue;

512

continue;

513

if (unlikely(pid_ns->child_reaper == father))

513

if (unlikely(pid_ns->child_reaper == father))

514

pid_ns->child_reaper = thread;

514

pid_ns->child_reaper = thread;

515

return thread;

515

return thread;

516

}

516

}

517

518

if (unlikely(pid_ns->child_reaper == father)) {

518

if (unlikely(pid_ns->child_reaper == father)) {

519

write_unlock_irq(&tasklist_lock);

519

write_unlock_irq(&tasklist_lock);

520

if (unlikely(pid_ns == &init_pid_ns)) {

520

if (unlikely(pid_ns == &init_pid_ns)) {

521

panic("Attempted to kill init! exitcode=0x%08x\n",

521

panic("Attempted to kill init! exitcode=0x%08x\n",

522

father->signal->group_exit_code ?:

522

father->signal->group_exit_code ?:

523

father->exit_code);

523

father->exit_code);

524

}

524

}

525

526

zap_pid_ns_processes(pid_ns);

526

zap_pid_ns_processes(pid_ns);

527

write_lock_irq(&tasklist_lock);

527

write_lock_irq(&tasklist_lock);

528

} else if (father->signal->has_child_subreaper) {

528

} else if (father->signal->has_child_subreaper) {

529

struct task_struct *reaper;

529

struct task_struct *reaper;

530

531

/*

531

/*

532

* Find the first ancestor marked as child_subreaper.

532

* Find the first ancestor marked as child_subreaper.

533

* Note that the code below checks same_thread_group(reaper,

533

* Note that the code below checks same_thread_group(reaper,

534

* pid_ns->child_reaper). This is what we need to DTRT in a

534

* pid_ns->child_reaper). This is what we need to DTRT in a

535

* PID namespace. However we still need the check above, see

535

* PID namespace. However we still need the check above, see

536

* http://marc.info/?l=linux-kernel&m=131385460420380

536

* http://marc.info/?l=linux-kernel&m=131385460420380

537

*/

537

*/

538

for (reaper = father->real_parent;

538

for (reaper = father->real_parent;

539

reaper != &init_task;

539

reaper != &init_task;

540

reaper = reaper->real_parent) {

540

reaper = reaper->real_parent) {

541

if (same_thread_group(reaper, pid_ns->child_reaper))

541

if (same_thread_group(reaper, pid_ns->child_reaper))

542

break;

542

break;

543

if (!reaper->signal->is_child_subreaper)

543

if (!reaper->signal->is_child_subreaper)

544

continue;

544

continue;

545

thread = reaper;

545

thread = reaper;

546

do {

546

do {

547

if (!(thread->flags & PF_EXITING))

547

if (!(thread->flags & PF_EXITING))

548

return reaper;

548

return reaper;

549

} while_each_thread(reaper, thread);

549

} while_each_thread(reaper, thread);

550

}

550

}

551

}

551

}

552

553

return pid_ns->child_reaper;

553

return pid_ns->child_reaper;

554

}

554

}

555

556

/*

556

/*

557

* Any that need to be release_task'd are put on the @dead list.

557

* Any that need to be release_task'd are put on the @dead list.

558

*/

558

*/

559

static void reparent_leader(struct task_struct *father, struct task_struct *p,

559

static void reparent_leader(struct task_struct *father, struct task_struct *p,

560

struct list_head *dead)

560

struct list_head *dead)

561

{

561

{

562

list_move_tail(&p->sibling, &p->real_parent->children);

562

list_move_tail(&p->sibling, &p->real_parent->children);

563

/*

563

/*

564

* If this is a threaded reparent there is no need to

564

* If this is a threaded reparent there is no need to

565

* notify anyone anything has happened.

565

* notify anyone anything has happened.

566

*/

566

*/

567

if (same_thread_group(p->real_parent, father))

567

if (same_thread_group(p->real_parent, father))

568

return;

568

return;

569

570

/*

570

/*

571

* We don't want people slaying init.

571

* We don't want people slaying init.

572

*

572

*

573

* Note: we do this even if it is EXIT_DEAD, wait_task_zombie()

573

* Note: we do this even if it is EXIT_DEAD, wait_task_zombie()

574

* can change ->exit_state to EXIT_ZOMBIE. If this is the final

574

* can change ->exit_state to EXIT_ZOMBIE. If this is the final

575

* state, do_notify_parent() was already called and ->exit_signal

575

* state, do_notify_parent() was already called and ->exit_signal

576

* doesn't matter.

576

* doesn't matter.

577

*/

577

*/

578

p->exit_signal = SIGCHLD;

578

p->exit_signal = SIGCHLD;

579

580

if (p->exit_state == EXIT_DEAD)

580

if (p->exit_state == EXIT_DEAD)

581

return;

581

return;

582

583

/* If it has exited notify the new parent about this child's death. */

583

/* If it has exited notify the new parent about this child's death. */

584

if (!p->ptrace &&

584

if (!p->ptrace &&

585

p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {

585

p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {

586

if (do_notify_parent(p, p->exit_signal)) {

586

if (do_notify_parent(p, p->exit_signal)) {

587

p->exit_state = EXIT_DEAD;

587

p->exit_state = EXIT_DEAD;

588

list_move_tail(&p->sibling, dead);

588

list_move_tail(&p->sibling, dead);

589

}

589

}

590

}

590

}

591

592

kill_orphaned_pgrp(p, father);

592

kill_orphaned_pgrp(p, father);

593

}

593

}

594

595

static void forget_original_parent(struct task_struct *father)

595

static void forget_original_parent(struct task_struct *father)

596

{

596

{

597

struct task_struct *p, *n, *reaper;

597

struct task_struct *p, *n, *reaper;

598

LIST_HEAD(dead_children);

598

LIST_HEAD(dead_children);

599

600

write_lock_irq(&tasklist_lock);

600

write_lock_irq(&tasklist_lock);

601

/*

601

/*

602

* Note that exit_ptrace() and find_new_reaper() might

602

* Note that exit_ptrace() and find_new_reaper() might

603

* drop tasklist_lock and reacquire it.

603

* drop tasklist_lock and reacquire it.

604

*/

604

*/

605

exit_ptrace(father);

605

exit_ptrace(father);

606

reaper = find_new_reaper(father);

606

reaper = find_new_reaper(father);

607

608

list_for_each_entry_safe(p, n, &father->children, sibling) {

608

list_for_each_entry_safe(p, n, &father->children, sibling) {

609

struct task_struct *t = p;

609

struct task_struct *t = p;

610

do {

610

do {

611

t->real_parent = reaper;

611

t->real_parent = reaper;

612

if (t->parent == father) {

612

if (t->parent == father) {

613

BUG_ON(t->ptrace);

613

BUG_ON(t->ptrace);

614

t->parent = t->real_parent;

614

t->parent = t->real_parent;

615

}

615

}

616

if (t->pdeath_signal)

616

if (t->pdeath_signal)

617

group_send_sig_info(t->pdeath_signal,

617

group_send_sig_info(t->pdeath_signal,

618

SEND_SIG_NOINFO, t);

618

SEND_SIG_NOINFO, t);

619

} while_each_thread(p, t);

619

} while_each_thread(p, t);

620

reparent_leader(father, p, &dead_children);

620

reparent_leader(father, p, &dead_children);

621

}

621

}

622

write_unlock_irq(&tasklist_lock);

622

write_unlock_irq(&tasklist_lock);

623

624

BUG_ON(!list_empty(&father->children));

624

BUG_ON(!list_empty(&father->children));

625

626

list_for_each_entry_safe(p, n, &dead_children, sibling) {

626

list_for_each_entry_safe(p, n, &dead_children, sibling) {

627

list_del_init(&p->sibling);

627

list_del_init(&p->sibling);

628

release_task(p);

628

release_task(p);

629

}

629

}

630

}

630

}

631

632

/*

632

/*

633

* Send signals to all our closest relatives so that they know

633

* Send signals to all our closest relatives so that they know

634

* to properly mourn us..

634

* to properly mourn us..

635

*/

635

*/

636

static void exit_notify(struct task_struct *tsk, int group_dead)

636

static void exit_notify(struct task_struct *tsk, int group_dead)

637

{

637

{

638

bool autoreap;

638

bool autoreap;

639

640

/*

640

/*

641

* This does two things:

641

* This does two things:

642

*

642

*

643

* A. Make init inherit all the child processes

643

* A. Make init inherit all the child processes

644

* B. Check to see if any process groups have become orphaned

644

* B. Check to see if any process groups have become orphaned

645

* as a result of our exiting, and if they have any stopped

645

* as a result of our exiting, and if they have any stopped

646

* jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)

646

* jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)

647

*/

647

*/

648

forget_original_parent(tsk);

648

forget_original_parent(tsk);

649

650

write_lock_irq(&tasklist_lock);

650

write_lock_irq(&tasklist_lock);

651

if (group_dead)

651

if (group_dead)

652

kill_orphaned_pgrp(tsk->group_leader, NULL);

652

kill_orphaned_pgrp(tsk->group_leader, NULL);

653

654

if (unlikely(tsk->ptrace)) {

654

if (unlikely(tsk->ptrace)) {

655

int sig = thread_group_leader(tsk) &&

655

int sig = thread_group_leader(tsk) &&

656

thread_group_empty(tsk) &&

656

thread_group_empty(tsk) &&

657

!ptrace_reparented(tsk) ?

657

!ptrace_reparented(tsk) ?

658

tsk->exit_signal : SIGCHLD;

658

tsk->exit_signal : SIGCHLD;

659

autoreap = do_notify_parent(tsk, sig);

659

autoreap = do_notify_parent(tsk, sig);

660

} else if (thread_group_leader(tsk)) {

660

} else if (thread_group_leader(tsk)) {

661

autoreap = thread_group_empty(tsk) &&

661

autoreap = thread_group_empty(tsk) &&

662

do_notify_parent(tsk, tsk->exit_signal);

662

do_notify_parent(tsk, tsk->exit_signal);

663

} else {

663

} else {

664

autoreap = true;

664

autoreap = true;

665

}

665

}

666

667

tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;

667

tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;

668

669

/* mt-exec, de_thread() is waiting for group leader */

669

/* mt-exec, de_thread() is waiting for group leader */

670

if (unlikely(tsk->signal->notify_count < 0))

670

if (unlikely(tsk->signal->notify_count < 0))

671

wake_up_process(tsk->signal->group_exit_task);

671

wake_up_process(tsk->signal->group_exit_task);

672

write_unlock_irq(&tasklist_lock);

672

write_unlock_irq(&tasklist_lock);

673

674

/* If the process is dead, release it - nobody will wait for it */

674

/* If the process is dead, release it - nobody will wait for it */

675

if (autoreap)

675

if (autoreap)

676

release_task(tsk);

676

release_task(tsk);

677

}

677

}

678

679

#ifdef CONFIG_DEBUG_STACK_USAGE

679

#ifdef CONFIG_DEBUG_STACK_USAGE

680

static void check_stack_usage(void)

680

static void check_stack_usage(void)

681

{

681

{

682

static DEFINE_SPINLOCK(low_water_lock);

682

static DEFINE_SPINLOCK(low_water_lock);

683

static int lowest_to_date = THREAD_SIZE;

683

static int lowest_to_date = THREAD_SIZE;

684

unsigned long free;

684

unsigned long free;

685

686

free = stack_not_used(current);

686

free = stack_not_used(current);

687

688

if (free >= lowest_to_date)

688

if (free >= lowest_to_date)

689

return;

689

return;

690

691

spin_lock(&low_water_lock);

691

spin_lock(&low_water_lock);

692

if (free < lowest_to_date) {

692

if (free < lowest_to_date) {

693

printk(KERN_WARNING "%s (%d) used greatest stack depth: "

693

printk(KERN_WARNING "%s (%d) used greatest stack depth: "

694

"%lu bytes left\n",

694

"%lu bytes left\n",

695

current->comm, task_pid_nr(current), free);

695

current->comm, task_pid_nr(current), free);

696

lowest_to_date = free;

696

lowest_to_date = free;

697

}

697

}

698

spin_unlock(&low_water_lock);

698

spin_unlock(&low_water_lock);

699

}

699

}

700

#else

700

#else

701

static inline void check_stack_usage(void) {}

701

static inline void check_stack_usage(void) {}

702

#endif

702

#endif

703

704

void do_exit(long code)

704

void do_exit(long code)

705

{

705

{

706

struct task_struct *tsk = current;

706

struct task_struct *tsk = current;

707

int group_dead;

707

int group_dead;

708

709

profile_task_exit(tsk);

709

profile_task_exit(tsk);

710

711

WARN_ON(blk_needs_flush_plug(tsk));

711

WARN_ON(blk_needs_flush_plug(tsk));

712

713

if (unlikely(in_interrupt()))

713

if (unlikely(in_interrupt()))

714

panic("Aiee, killing interrupt handler!");

714

panic("Aiee, killing interrupt handler!");

715

if (unlikely(!tsk->pid))

715

if (unlikely(!tsk->pid))

716

panic("Attempted to kill the idle task!");

716

panic("Attempted to kill the idle task!");

717

718

/*

718

/*

719

* If do_exit is called because this processes oopsed, it's possible

719

* If do_exit is called because this processes oopsed, it's possible

720

* that get_fs() was left as KERNEL_DS, so reset it to USER_DS before

720

* that get_fs() was left as KERNEL_DS, so reset it to USER_DS before

721

* continuing. Amongst other possible reasons, this is to prevent

721

* continuing. Amongst other possible reasons, this is to prevent

722

* mm_release()->clear_child_tid() from writing to a user-controlled

722

* mm_release()->clear_child_tid() from writing to a user-controlled

723

* kernel address.

723

* kernel address.

724

*/

724

*/

725

set_fs(USER_DS);

725

set_fs(USER_DS);

726

727

ptrace_event(PTRACE_EVENT_EXIT, code);

727

ptrace_event(PTRACE_EVENT_EXIT, code);

728

729

validate_creds_for_do_exit(tsk);

729

validate_creds_for_do_exit(tsk);

730

731

/*

731

/*

732

* We're taking recursive faults here in do_exit. Safest is to just

732

* We're taking recursive faults here in do_exit. Safest is to just

733

* leave this task alone and wait for reboot.

733

* leave this task alone and wait for reboot.

734

*/

734

*/

735

if (unlikely(tsk->flags & PF_EXITING)) {

735

if (unlikely(tsk->flags & PF_EXITING)) {

736

printk(KERN_ALERT

736

printk(KERN_ALERT

737

"Fixing recursive fault but reboot is needed!\n");

737

"Fixing recursive fault but reboot is needed!\n");

738

/*

738

/*

739

* We can do this unlocked here. The futex code uses

739

* We can do this unlocked here. The futex code uses

740

* this flag just to verify whether the pi state

740

* this flag just to verify whether the pi state

741

* cleanup has been done or not. In the worst case it

741

* cleanup has been done or not. In the worst case it

742

* loops once more. We pretend that the cleanup was

742

* loops once more. We pretend that the cleanup was

743

* done as there is no way to return. Either the

743

* done as there is no way to return. Either the

744

* OWNER_DIED bit is set by now or we push the blocked

744

* OWNER_DIED bit is set by now or we push the blocked

745

* task into the wait for ever nirwana as well.

745

* task into the wait for ever nirwana as well.

746

*/

746

*/

747

tsk->flags |= PF_EXITPIDONE;

747

tsk->flags |= PF_EXITPIDONE;

748

set_current_state(TASK_UNINTERRUPTIBLE);

748

set_current_state(TASK_UNINTERRUPTIBLE);

749

schedule();

749

schedule();

750

}

750

}

751

752

exit_signals(tsk); /* sets PF_EXITING */

752

exit_signals(tsk); /* sets PF_EXITING */

753

/*

753

/*

754

* tsk->flags are checked in the futex code to protect against

754

* tsk->flags are checked in the futex code to protect against

755

* an exiting task cleaning up the robust pi futexes.

755

* an exiting task cleaning up the robust pi futexes.

756

*/

756

*/

757

smp_mb();

757

smp_mb();

758

raw_spin_unlock_wait(&tsk->pi_lock);

758

raw_spin_unlock_wait(&tsk->pi_lock);

759

760

if (unlikely(in_atomic()))

760

if (unlikely(in_atomic()))

761

printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",

761

printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",

762

current->comm, task_pid_nr(current),

762

current->comm, task_pid_nr(current),

763

preempt_count());

763

preempt_count());

764

765

acct_update_integrals(tsk);

765

acct_update_integrals(tsk);

766

/* sync mm's RSS info before statistics gathering */

766

/* sync mm's RSS info before statistics gathering */

767

if (tsk->mm)

767

if (tsk->mm)

768

sync_mm_rss(tsk->mm);

768

sync_mm_rss(tsk->mm);

769

group_dead = atomic_dec_and_test(&tsk->signal->live);

769

group_dead = atomic_dec_and_test(&tsk->signal->live);

770

if (group_dead) {

770

if (group_dead) {

771

hrtimer_cancel(&tsk->signal->real_timer);

771

hrtimer_cancel(&tsk->signal->real_timer);

772

exit_itimers(tsk->signal);

772

exit_itimers(tsk->signal);

773

if (tsk->mm)

773

if (tsk->mm)

774

setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);

774

setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);

775

}

775

}

776

acct_collect(code, group_dead);

776

acct_collect(code, group_dead);

777

if (group_dead)

777

if (group_dead)

778

tty_audit_exit();

778

tty_audit_exit();

779

audit_free(tsk);

779

audit_free(tsk);

780

781

tsk->exit_code = code;

781

tsk->exit_code = code;

782

taskstats_exit(tsk, group_dead);

782

taskstats_exit(tsk, group_dead);

783

784

exit_mm(tsk);

784

exit_mm(tsk);

785

786

if (group_dead)

786

if (group_dead)

787

acct_process();

787

acct_process();

788

trace_sched_process_exit(tsk);

788

trace_sched_process_exit(tsk);

789

790

exit_sem(tsk);

790

exit_sem(tsk);

791

exit_shm(tsk);

791

exit_shm(tsk);

792

exit_files(tsk);

792

exit_files(tsk);

793

exit_fs(tsk);

793

exit_fs(tsk);

794

if (group_dead)

795

disassociate_ctty(1);

794

exit_task_namespaces(tsk);

796

exit_task_namespaces(tsk);

795

exit_task_work(tsk);

797

exit_task_work(tsk);

796

check_stack_usage();

798

check_stack_usage();

797

exit_thread();

799

exit_thread();

798

800

799

/*

801

/*

800

* Flush inherited counters to the parent - before the parent

802

* Flush inherited counters to the parent - before the parent

801

* gets woken up by child-exit notifications.

803

* gets woken up by child-exit notifications.

802

*

804

*

803

* because of cgroup mode, must be called before cgroup_exit()

805

* because of cgroup mode, must be called before cgroup_exit()

804

*/

806

*/

805

perf_event_exit_task(tsk);

807

perf_event_exit_task(tsk);

806

808

807

cgroup_exit(tsk, 1);

809

cgroup_exit(tsk, 1);

808

810

809

if (group_dead)

810

disassociate_ctty(1);

811

812

module_put(task_thread_info(tsk)->exec_domain->module);

811

module_put(task_thread_info(tsk)->exec_domain->module);

813

812

814

proc_exit_connector(tsk);

813

proc_exit_connector(tsk);

815

816

/*

814

/*

817

* FIXME: do that only when needed, using sched_exit tracepoint

815

* FIXME: do that only when needed, using sched_exit tracepoint

818

*/

816

*/

819

flush_ptrace_hw_breakpoint(tsk);

817

flush_ptrace_hw_breakpoint(tsk);

820

818

821

exit_notify(tsk, group_dead);

819

exit_notify(tsk, group_dead);

822

#ifdef CONFIG_NUMA

820

#ifdef CONFIG_NUMA

823

task_lock(tsk);

821

task_lock(tsk);

824

mpol_put(tsk->mempolicy);

822

mpol_put(tsk->mempolicy);

825

tsk->mempolicy = NULL;

823

tsk->mempolicy = NULL;

826

task_unlock(tsk);

824

task_unlock(tsk);

827

#endif

825

#endif

828

#ifdef CONFIG_FUTEX

826

#ifdef CONFIG_FUTEX

829

if (unlikely(current->pi_state_cache))

827

if (unlikely(current->pi_state_cache))

830

kfree(current->pi_state_cache);

828

kfree(current->pi_state_cache);

831

#endif

829

#endif

832

/*

830

/*

833

* Make sure we are holding no locks:

831

* Make sure we are holding no locks:

834

*/

832

*/

835

debug_check_no_locks_held();

833

debug_check_no_locks_held();

836

/*

834

/*

837

* We can do this unlocked here. The futex code uses this flag

835

* We can do this unlocked here. The futex code uses this flag

838

* just to verify whether the pi state cleanup has been done

836

* just to verify whether the pi state cleanup has been done

839

* or not. In the worst case it loops once more.

837

* or not. In the worst case it loops once more.

840

*/

838

*/

841

tsk->flags |= PF_EXITPIDONE;

839

tsk->flags |= PF_EXITPIDONE;

842

840

843

if (tsk->io_context)

841

if (tsk->io_context)

844

exit_io_context(tsk);

842

exit_io_context(tsk);

845

843

846

if (tsk->splice_pipe)

844

if (tsk->splice_pipe)

847

free_pipe_info(tsk->splice_pipe);

845

free_pipe_info(tsk->splice_pipe);

848

846

849

if (tsk->task_frag.page)

847

if (tsk->task_frag.page)

850

put_page(tsk->task_frag.page);

848

put_page(tsk->task_frag.page);

851

849

852

validate_creds_for_do_exit(tsk);

850

validate_creds_for_do_exit(tsk);

853

851

854

preempt_disable();

852

preempt_disable();

855

if (tsk->nr_dirtied)

853

if (tsk->nr_dirtied)

856

__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);

854

__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);

857

exit_rcu();

855

exit_rcu();

858

856

859

/*

857

/*

860

* The setting of TASK_RUNNING by try_to_wake_up() may be delayed

858

* The setting of TASK_RUNNING by try_to_wake_up() may be delayed

861

* when the following two conditions become true.

859

* when the following two conditions become true.

862

* - There is race condition of mmap_sem (It is acquired by

860

* - There is race condition of mmap_sem (It is acquired by

863

* exit_mm()), and

861

* exit_mm()), and

864

* - SMI occurs before setting TASK_RUNINNG.

862

* - SMI occurs before setting TASK_RUNINNG.

865

* (or hypervisor of virtual machine switches to other guest)

863

* (or hypervisor of virtual machine switches to other guest)

866

* As a result, we may become TASK_RUNNING after becoming TASK_DEAD

864

* As a result, we may become TASK_RUNNING after becoming TASK_DEAD

867

*

865

*

868

* To avoid it, we have to wait for releasing tsk->pi_lock which

866

* To avoid it, we have to wait for releasing tsk->pi_lock which

869

* is held by try_to_wake_up()

867

* is held by try_to_wake_up()

870

*/

868

*/

871

smp_mb();

869

smp_mb();

872

raw_spin_unlock_wait(&tsk->pi_lock);

870

raw_spin_unlock_wait(&tsk->pi_lock);

873

871

874

/* causes final put_task_struct in finish_task_switch(). */

872

/* causes final put_task_struct in finish_task_switch(). */

875

tsk->state = TASK_DEAD;

873

tsk->state = TASK_DEAD;

876

tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */

874

tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */

877

schedule();

875

schedule();

878

BUG();

876

BUG();

879

/* Avoid "noreturn function does return". */

877

/* Avoid "noreturn function does return". */

880

for (;;)

878

for (;;)

881

cpu_relax(); /* For when BUG is null */

879

cpu_relax(); /* For when BUG is null */

882

}

880

}

883

881

884

EXPORT_SYMBOL_GPL(do_exit);

882

EXPORT_SYMBOL_GPL(do_exit);

885

883

886

void complete_and_exit(struct completion *comp, long code)

884

void complete_and_exit(struct completion *comp, long code)

887

{

885

{

888

if (comp)

886

if (comp)

889

complete(comp);

887

complete(comp);

890

888

891

do_exit(code);

889

do_exit(code);

892

}

890

}

893

891

894

EXPORT_SYMBOL(complete_and_exit);

892

EXPORT_SYMBOL(complete_and_exit);

895

893

896

SYSCALL_DEFINE1(exit, int, error_code)

894

SYSCALL_DEFINE1(exit, int, error_code)

897

{

895

{

898

do_exit((error_code&0xff)<<8);

896

do_exit((error_code&0xff)<<8);

899

}

897

}

900

898

901

/*

899

/*

902

* Take down every thread in the group. This is called by fatal signals

900

* Take down every thread in the group. This is called by fatal signals

903

* as well as by sys_exit_group (below).

901

* as well as by sys_exit_group (below).

904

*/

902

*/

905

void

903

void

906

do_group_exit(int exit_code)

904

do_group_exit(int exit_code)

907

{

905

{

908

struct signal_struct *sig = current->signal;

906

struct signal_struct *sig = current->signal;

909

907

910

BUG_ON(exit_code & 0x80); /* core dumps don't get here */

908

BUG_ON(exit_code & 0x80); /* core dumps don't get here */

911

909

912

if (signal_group_exit(sig))

910

if (signal_group_exit(sig))

913

exit_code = sig->group_exit_code;

911

exit_code = sig->group_exit_code;

914

else if (!thread_group_empty(current)) {

912

else if (!thread_group_empty(current)) {

915

struct sighand_struct *const sighand = current->sighand;

913

struct sighand_struct *const sighand = current->sighand;

916

spin_lock_irq(&sighand->siglock);

914

spin_lock_irq(&sighand->siglock);

917

if (signal_group_exit(sig))

915

if (signal_group_exit(sig))

918

/* Another thread got here before we took the lock. */

916

/* Another thread got here before we took the lock. */

919

exit_code = sig->group_exit_code;

917

exit_code = sig->group_exit_code;

920

else {

918

else {

921

sig->group_exit_code = exit_code;

919

sig->group_exit_code = exit_code;

922

sig->flags = SIGNAL_GROUP_EXIT;

920

sig->flags = SIGNAL_GROUP_EXIT;

923

zap_other_threads(current);

921

zap_other_threads(current);

924

}

922

}

925

spin_unlock_irq(&sighand->siglock);

923

spin_unlock_irq(&sighand->siglock);

926

}

924

}

927

925

928

do_exit(exit_code);

926

do_exit(exit_code);

929

/* NOTREACHED */

927

/* NOTREACHED */

930

}

928

}

931

929

932

/*

930

/*

933

* this kills every thread in the thread group. Note that any externally

931

* this kills every thread in the thread group. Note that any externally

934

* wait4()-ing process will get the correct exit code - even if this

932

* wait4()-ing process will get the correct exit code - even if this

935

* thread is not the thread group leader.

933

* thread is not the thread group leader.

936

*/

934

*/

937

SYSCALL_DEFINE1(exit_group, int, error_code)

935

SYSCALL_DEFINE1(exit_group, int, error_code)

938

{

936

{

939

do_group_exit((error_code & 0xff) << 8);

937

do_group_exit((error_code & 0xff) << 8);

940

/* NOTREACHED */

938

/* NOTREACHED */

941

return 0;

939

return 0;

942

}

940

}

943

941

944

struct wait_opts {

942

struct wait_opts {

945

enum pid_type wo_type;

943

enum pid_type wo_type;

946

int wo_flags;

944

int wo_flags;

947

struct pid *wo_pid;

945

struct pid *wo_pid;

948

946

949

struct siginfo __user *wo_info;

947

struct siginfo __user *wo_info;

950

int __user *wo_stat;

948

int __user *wo_stat;

951

struct rusage __user *wo_rusage;

949

struct rusage __user *wo_rusage;

952

950

953

wait_queue_t child_wait;

951

wait_queue_t child_wait;

954

int notask_error;

952

int notask_error;

955

};

953

};

956

954

957

static inline

955

static inline

958

struct pid *task_pid_type(struct task_struct *task, enum pid_type type)

956

struct pid *task_pid_type(struct task_struct *task, enum pid_type type)

959

{

957

{

960

if (type != PIDTYPE_PID)

958

if (type != PIDTYPE_PID)

961

task = task->group_leader;

959

task = task->group_leader;

962

return task->pids[type].pid;

960

return task->pids[type].pid;

963

}

961

}

964

962

965

static int eligible_pid(struct wait_opts *wo, struct task_struct *p)

963

static int eligible_pid(struct wait_opts *wo, struct task_struct *p)

966

{

964

{

967

return wo->wo_type == PIDTYPE_MAX ||

965

return wo->wo_type == PIDTYPE_MAX ||

968

task_pid_type(p, wo->wo_type) == wo->wo_pid;

966

task_pid_type(p, wo->wo_type) == wo->wo_pid;

969

}

967

}

970

968

971

static int eligible_child(struct wait_opts *wo, struct task_struct *p)

969

static int eligible_child(struct wait_opts *wo, struct task_struct *p)

972

{

970

{

973

if (!eligible_pid(wo, p))

971

if (!eligible_pid(wo, p))

974

return 0;

972

return 0;

975

/* Wait for all children (clone and not) if __WALL is set;

973

/* Wait for all children (clone and not) if __WALL is set;

976

* otherwise, wait for clone children *only* if __WCLONE is

974

* otherwise, wait for clone children *only* if __WCLONE is

977

* set; otherwise, wait for non-clone children *only*. (Note:

975

* set; otherwise, wait for non-clone children *only*. (Note:

978

* A "clone" child here is one that reports to its parent

976

* A "clone" child here is one that reports to its parent

979

* using a signal other than SIGCHLD.) */

977

* using a signal other than SIGCHLD.) */

980

if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))

978

if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))

981

&& !(wo->wo_flags & __WALL))

979

&& !(wo->wo_flags & __WALL))

982

return 0;

980

return 0;

983

981

984

return 1;

982

return 1;

985

}

983

}

986

984

987

static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,

985

static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,

988

pid_t pid, uid_t uid, int why, int status)

986

pid_t pid, uid_t uid, int why, int status)

989

{

987

{

990

struct siginfo __user *infop;

988

struct siginfo __user *infop;

991

int retval = wo->wo_rusage

989

int retval = wo->wo_rusage

992

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

990

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

993

991

994

put_task_struct(p);

992

put_task_struct(p);

995

infop = wo->wo_info;

993

infop = wo->wo_info;

996

if (infop) {

994

if (infop) {

997

if (!retval)

995

if (!retval)

998

retval = put_user(SIGCHLD, &infop->si_signo);

996

retval = put_user(SIGCHLD, &infop->si_signo);

999

if (!retval)

997

if (!retval)

1000

retval = put_user(0, &infop->si_errno);

998

retval = put_user(0, &infop->si_errno);

1001

if (!retval)

999

if (!retval)

1002

retval = put_user((short)why, &infop->si_code);

1000

retval = put_user((short)why, &infop->si_code);

1003

if (!retval)

1001

if (!retval)

1004

retval = put_user(pid, &infop->si_pid);

1002

retval = put_user(pid, &infop->si_pid);

1005

if (!retval)

1003

if (!retval)

1006

retval = put_user(uid, &infop->si_uid);

1004

retval = put_user(uid, &infop->si_uid);

1007

if (!retval)

1005

if (!retval)

1008

retval = put_user(status, &infop->si_status);

1006

retval = put_user(status, &infop->si_status);

1009

}

1007

}

1010

if (!retval)

1008

if (!retval)

1011

retval = pid;

1009

retval = pid;

1012

return retval;

1010

return retval;

1013

}

1011

}

1014

1012

1015

/*

1013

/*

1016

* Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold

1014

* Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold

1017

* read_lock(&tasklist_lock) on entry. If we return zero, we still hold

1015

* read_lock(&tasklist_lock) on entry. If we return zero, we still hold

1018

* the lock and this task is uninteresting. If we return nonzero, we have

1016

* the lock and this task is uninteresting. If we return nonzero, we have

1019

* released the lock and the system call should return.

1017

* released the lock and the system call should return.

1020

*/

1018

*/

1021

static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)

1019

static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)

1022

{

1020

{

1023

unsigned long state;

1021

unsigned long state;

1024

int retval, status, traced;

1022

int retval, status, traced;

1025

pid_t pid = task_pid_vnr(p);

1023

pid_t pid = task_pid_vnr(p);

1026

uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));

1024

uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));

1027

struct siginfo __user *infop;

1025

struct siginfo __user *infop;

1028

1026

1029

if (!likely(wo->wo_flags & WEXITED))

1027

if (!likely(wo->wo_flags & WEXITED))

1030

return 0;

1028

return 0;

1031

1029

1032

if (unlikely(wo->wo_flags & WNOWAIT)) {

1030

if (unlikely(wo->wo_flags & WNOWAIT)) {

1033

int exit_code = p->exit_code;

1031

int exit_code = p->exit_code;

1034

int why;

1032

int why;

1035

1033

1036

get_task_struct(p);

1034

get_task_struct(p);

1037

read_unlock(&tasklist_lock);

1035

read_unlock(&tasklist_lock);

1038

if ((exit_code & 0x7f) == 0) {

1036

if ((exit_code & 0x7f) == 0) {

1039

why = CLD_EXITED;

1037

why = CLD_EXITED;

1040

status = exit_code >> 8;

1038

status = exit_code >> 8;

1041

} else {

1039

} else {

1042

why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;

1040

why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;

1043

status = exit_code & 0x7f;

1041

status = exit_code & 0x7f;

1044

}

1042

}

1045

return wait_noreap_copyout(wo, p, pid, uid, why, status);

1043

return wait_noreap_copyout(wo, p, pid, uid, why, status);

1046

}

1044

}

1047

1045

1048

/*

1046

/*

1049

* Try to move the task's state to DEAD

1047

* Try to move the task's state to DEAD

1050

* only one thread is allowed to do this:

1048

* only one thread is allowed to do this:

1051

*/

1049

*/

1052

state = xchg(&p->exit_state, EXIT_DEAD);

1050

state = xchg(&p->exit_state, EXIT_DEAD);

1053

if (state != EXIT_ZOMBIE) {

1051

if (state != EXIT_ZOMBIE) {

1054

BUG_ON(state != EXIT_DEAD);

1052

BUG_ON(state != EXIT_DEAD);

1055

return 0;

1053

return 0;

1056

}

1054

}

1057

1055

1058

traced = ptrace_reparented(p);

1056

traced = ptrace_reparented(p);

1059

/*

1057

/*

1060

* It can be ptraced but not reparented, check

1058

* It can be ptraced but not reparented, check

1061

* thread_group_leader() to filter out sub-threads.

1059

* thread_group_leader() to filter out sub-threads.

1062

*/

1060

*/

1063

if (likely(!traced) && thread_group_leader(p)) {

1061

if (likely(!traced) && thread_group_leader(p)) {

1064

struct signal_struct *psig;

1062

struct signal_struct *psig;

1065

struct signal_struct *sig;

1063

struct signal_struct *sig;

1066

unsigned long maxrss;

1064

unsigned long maxrss;

1067

cputime_t tgutime, tgstime;

1065

cputime_t tgutime, tgstime;

1068

1066

1069

/*

1067

/*

1070

* The resource counters for the group leader are in its

1068

* The resource counters for the group leader are in its

1071

* own task_struct. Those for dead threads in the group

1069

* own task_struct. Those for dead threads in the group

1072

* are in its signal_struct, as are those for the child

1070

* are in its signal_struct, as are those for the child

1073

* processes it has previously reaped. All these

1071

* processes it has previously reaped. All these

1074

* accumulate in the parent's signal_struct c* fields.

1072

* accumulate in the parent's signal_struct c* fields.

1075

*

1073

*

1076

* We don't bother to take a lock here to protect these

1074

* We don't bother to take a lock here to protect these

1077

* p->signal fields, because they are only touched by

1075

* p->signal fields, because they are only touched by

1078

* __exit_signal, which runs with tasklist_lock

1076

* __exit_signal, which runs with tasklist_lock

1079

* write-locked anyway, and so is excluded here. We do

1077

* write-locked anyway, and so is excluded here. We do

1080

* need to protect the access to parent->signal fields,

1078

* need to protect the access to parent->signal fields,

1081

* as other threads in the parent group can be right

1079

* as other threads in the parent group can be right

1082

* here reaping other children at the same time.

1080

* here reaping other children at the same time.

1083

*

1081

*

1084

* We use thread_group_cputime_adjusted() to get times for the thread

1082

* We use thread_group_cputime_adjusted() to get times for the thread

1085

* group, which consolidates times for all threads in the

1083

* group, which consolidates times for all threads in the

1086

* group including the group leader.

1084

* group including the group leader.

1087

*/

1085

*/

1088

thread_group_cputime_adjusted(p, &tgutime, &tgstime);

1086

thread_group_cputime_adjusted(p, &tgutime, &tgstime);

1089

spin_lock_irq(&p->real_parent->sighand->siglock);

1087

spin_lock_irq(&p->real_parent->sighand->siglock);

1090

psig = p->real_parent->signal;

1088

psig = p->real_parent->signal;

1091

sig = p->signal;

1089

sig = p->signal;

1092

psig->cutime += tgutime + sig->cutime;

1090

psig->cutime += tgutime + sig->cutime;

1093

psig->cstime += tgstime + sig->cstime;

1091

psig->cstime += tgstime + sig->cstime;

1094

psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;

1092

psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;

1095

psig->cmin_flt +=

1093

psig->cmin_flt +=

1096

p->min_flt + sig->min_flt + sig->cmin_flt;

1094

p->min_flt + sig->min_flt + sig->cmin_flt;

1097

psig->cmaj_flt +=

1095

psig->cmaj_flt +=

1098

p->maj_flt + sig->maj_flt + sig->cmaj_flt;

1096

p->maj_flt + sig->maj_flt + sig->cmaj_flt;

1099

psig->cnvcsw +=

1097

psig->cnvcsw +=

1100

p->nvcsw + sig->nvcsw + sig->cnvcsw;

1098

p->nvcsw + sig->nvcsw + sig->cnvcsw;

1101

psig->cnivcsw +=

1099

psig->cnivcsw +=

1102

p->nivcsw + sig->nivcsw + sig->cnivcsw;

1100

p->nivcsw + sig->nivcsw + sig->cnivcsw;

1103

psig->cinblock +=

1101

psig->cinblock +=

1104

task_io_get_inblock(p) +

1102

task_io_get_inblock(p) +

1105

sig->inblock + sig->cinblock;

1103

sig->inblock + sig->cinblock;

1106

psig->coublock +=

1104

psig->coublock +=

1107

task_io_get_oublock(p) +

1105

task_io_get_oublock(p) +

1108

sig->oublock + sig->coublock;

1106

sig->oublock + sig->coublock;

1109

maxrss = max(sig->maxrss, sig->cmaxrss);

1107

maxrss = max(sig->maxrss, sig->cmaxrss);

1110

if (psig->cmaxrss < maxrss)

1108

if (psig->cmaxrss < maxrss)

1111

psig->cmaxrss = maxrss;

1109

psig->cmaxrss = maxrss;

1112

task_io_accounting_add(&psig->ioac, &p->ioac);

1110

task_io_accounting_add(&psig->ioac, &p->ioac);

1113

task_io_accounting_add(&psig->ioac, &sig->ioac);

1111

task_io_accounting_add(&psig->ioac, &sig->ioac);

1114

spin_unlock_irq(&p->real_parent->sighand->siglock);

1112

spin_unlock_irq(&p->real_parent->sighand->siglock);

1115

}

1113

}

1116

1114

1117

/*

1115

/*

1118

* Now we are sure this task is interesting, and no other

1116

* Now we are sure this task is interesting, and no other

1119

* thread can reap it because we set its state to EXIT_DEAD.

1117

* thread can reap it because we set its state to EXIT_DEAD.

1120

*/

1118

*/

1121

read_unlock(&tasklist_lock);

1119

read_unlock(&tasklist_lock);

1122

1120

1123

retval = wo->wo_rusage

1121

retval = wo->wo_rusage

1124

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1122

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1125

status = (p->signal->flags & SIGNAL_GROUP_EXIT)

1123

status = (p->signal->flags & SIGNAL_GROUP_EXIT)

1126

? p->signal->group_exit_code : p->exit_code;

1124

? p->signal->group_exit_code : p->exit_code;

1127

if (!retval && wo->wo_stat)

1125

if (!retval && wo->wo_stat)

1128

retval = put_user(status, wo->wo_stat);

1126

retval = put_user(status, wo->wo_stat);

1129

1127

1130

infop = wo->wo_info;

1128

infop = wo->wo_info;

1131

if (!retval && infop)

1129

if (!retval && infop)

1132

retval = put_user(SIGCHLD, &infop->si_signo);

1130

retval = put_user(SIGCHLD, &infop->si_signo);

1133

if (!retval && infop)

1131

if (!retval && infop)

1134

retval = put_user(0, &infop->si_errno);

1132

retval = put_user(0, &infop->si_errno);

1135

if (!retval && infop) {

1133

if (!retval && infop) {

1136

int why;

1134

int why;

1137

1135

1138

if ((status & 0x7f) == 0) {

1136

if ((status & 0x7f) == 0) {

1139

why = CLD_EXITED;

1137

why = CLD_EXITED;

1140

status >>= 8;

1138

status >>= 8;

1141

} else {

1139

} else {

1142

why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;

1140

why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;

1143

status &= 0x7f;

1141

status &= 0x7f;

1144

}

1142

}

1145

retval = put_user((short)why, &infop->si_code);

1143

retval = put_user((short)why, &infop->si_code);

1146

if (!retval)

1144

if (!retval)

1147

retval = put_user(status, &infop->si_status);

1145

retval = put_user(status, &infop->si_status);

1148

}

1146

}

1149

if (!retval && infop)

1147

if (!retval && infop)

1150

retval = put_user(pid, &infop->si_pid);

1148

retval = put_user(pid, &infop->si_pid);

1151

if (!retval && infop)

1149

if (!retval && infop)

1152

retval = put_user(uid, &infop->si_uid);

1150

retval = put_user(uid, &infop->si_uid);

1153

if (!retval)

1151

if (!retval)

1154

retval = pid;

1152

retval = pid;

1155

1153

1156

if (traced) {

1154

if (traced) {

1157

write_lock_irq(&tasklist_lock);

1155

write_lock_irq(&tasklist_lock);

1158

/* We dropped tasklist, ptracer could die and untrace */

1156

/* We dropped tasklist, ptracer could die and untrace */

1159

ptrace_unlink(p);

1157

ptrace_unlink(p);

1160

/*

1158

/*

1161

* If this is not a sub-thread, notify the parent.

1159

* If this is not a sub-thread, notify the parent.

1162

* If parent wants a zombie, don't release it now.

1160

* If parent wants a zombie, don't release it now.

1163

*/

1161

*/

1164

if (thread_group_leader(p) &&

1162

if (thread_group_leader(p) &&

1165

!do_notify_parent(p, p->exit_signal)) {

1163

!do_notify_parent(p, p->exit_signal)) {

1166

p->exit_state = EXIT_ZOMBIE;

1164

p->exit_state = EXIT_ZOMBIE;

1167

p = NULL;

1165

p = NULL;

1168

}

1166

}

1169

write_unlock_irq(&tasklist_lock);

1167

write_unlock_irq(&tasklist_lock);

1170

}

1168

}

1171

if (p != NULL)

1169

if (p != NULL)

1172

release_task(p);

1170

release_task(p);

1173

1171

1174

return retval;

1172

return retval;

1175

}

1173

}

1176

1174

1177

static int *task_stopped_code(struct task_struct *p, bool ptrace)

1175

static int *task_stopped_code(struct task_struct *p, bool ptrace)

1178

{

1176

{

1179

if (ptrace) {

1177

if (ptrace) {

1180

if (task_is_stopped_or_traced(p) &&

1178

if (task_is_stopped_or_traced(p) &&

1181

!(p->jobctl & JOBCTL_LISTENING))

1179

!(p->jobctl & JOBCTL_LISTENING))

1182

return &p->exit_code;

1180

return &p->exit_code;

1183

} else {

1181

} else {

1184

if (p->signal->flags & SIGNAL_STOP_STOPPED)

1182

if (p->signal->flags & SIGNAL_STOP_STOPPED)

1185

return &p->signal->group_exit_code;

1183

return &p->signal->group_exit_code;

1186

}

1184

}

1187

return NULL;

1185

return NULL;

1188

}

1186

}

1189

1187

1190

/**

1188

/**

1191

* wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED

1189

* wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED

1192

* @wo: wait options

1190

* @wo: wait options

1193

* @ptrace: is the wait for ptrace

1191

* @ptrace: is the wait for ptrace

1194

* @p: task to wait for

1192

* @p: task to wait for

1195

*

1193

*

1196

* Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.

1194

* Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.

1197

*

1195

*

1198

* CONTEXT:

1196

* CONTEXT:

1199

* read_lock(&tasklist_lock), which is released if return value is

1197

* read_lock(&tasklist_lock), which is released if return value is

1200

* non-zero. Also, grabs and releases @p->sighand->siglock.

1198

* non-zero. Also, grabs and releases @p->sighand->siglock.

1201

*

1199

*

1202

* RETURNS:

1200

* RETURNS:

1203

* 0 if wait condition didn't exist and search for other wait conditions

1201

* 0 if wait condition didn't exist and search for other wait conditions

1204

* should continue. Non-zero return, -errno on failure and @p's pid on

1202

* should continue. Non-zero return, -errno on failure and @p's pid on

1205

* success, implies that tasklist_lock is released and wait condition

1203

* success, implies that tasklist_lock is released and wait condition

1206

* search should terminate.

1204

* search should terminate.

1207

*/

1205

*/

1208

static int wait_task_stopped(struct wait_opts *wo,

1206

static int wait_task_stopped(struct wait_opts *wo,

1209

int ptrace, struct task_struct *p)

1207

int ptrace, struct task_struct *p)

1210

{

1208

{

1211

struct siginfo __user *infop;

1209

struct siginfo __user *infop;

1212

int retval, exit_code, *p_code, why;

1210

int retval, exit_code, *p_code, why;

1213

uid_t uid = 0; /* unneeded, required by compiler */

1211

uid_t uid = 0; /* unneeded, required by compiler */

1214

pid_t pid;

1212

pid_t pid;

1215

1213

1216

/*

1214

/*

1217

* Traditionally we see ptrace'd stopped tasks regardless of options.

1215

* Traditionally we see ptrace'd stopped tasks regardless of options.

1218

*/

1216

*/

1219

if (!ptrace && !(wo->wo_flags & WUNTRACED))

1217

if (!ptrace && !(wo->wo_flags & WUNTRACED))

1220

return 0;

1218

return 0;

1221

1219

1222

if (!task_stopped_code(p, ptrace))

1220

if (!task_stopped_code(p, ptrace))

1223

return 0;

1221

return 0;

1224

1222

1225

exit_code = 0;

1223

exit_code = 0;

1226

spin_lock_irq(&p->sighand->siglock);

1224

spin_lock_irq(&p->sighand->siglock);

1227

1225

1228

p_code = task_stopped_code(p, ptrace);

1226

p_code = task_stopped_code(p, ptrace);

1229

if (unlikely(!p_code))

1227

if (unlikely(!p_code))

1230

goto unlock_sig;

1228

goto unlock_sig;

1231

1229

1232

exit_code = *p_code;

1230

exit_code = *p_code;

1233

if (!exit_code)

1231

if (!exit_code)

1234

goto unlock_sig;

1232

goto unlock_sig;

1235

1233

1236

if (!unlikely(wo->wo_flags & WNOWAIT))

1234

if (!unlikely(wo->wo_flags & WNOWAIT))

1237

*p_code = 0;

1235

*p_code = 0;

1238

1236

1239

uid = from_kuid_munged(current_user_ns(), task_uid(p));

1237

uid = from_kuid_munged(current_user_ns(), task_uid(p));

1240

unlock_sig:

1238

unlock_sig:

1241

spin_unlock_irq(&p->sighand->siglock);

1239

spin_unlock_irq(&p->sighand->siglock);

1242

if (!exit_code)

1240

if (!exit_code)

1243

return 0;

1241

return 0;

1244

1242

1245

/*

1243

/*

1246

* Now we are pretty sure this task is interesting.

1244

* Now we are pretty sure this task is interesting.

1247

* Make sure it doesn't get reaped out from under us while we

1245

* Make sure it doesn't get reaped out from under us while we

1248

* give up the lock and then examine it below. We don't want to

1246

* give up the lock and then examine it below. We don't want to

1249

* keep holding onto the tasklist_lock while we call getrusage and

1247

* keep holding onto the tasklist_lock while we call getrusage and

1250

* possibly take page faults for user memory.

1248

* possibly take page faults for user memory.

1251

*/

1249

*/

1252

get_task_struct(p);

1250

get_task_struct(p);

1253

pid = task_pid_vnr(p);

1251

pid = task_pid_vnr(p);

1254

why = ptrace ? CLD_TRAPPED : CLD_STOPPED;

1252

why = ptrace ? CLD_TRAPPED : CLD_STOPPED;

1255

read_unlock(&tasklist_lock);

1253

read_unlock(&tasklist_lock);

1256

1254

1257

if (unlikely(wo->wo_flags & WNOWAIT))

1255

if (unlikely(wo->wo_flags & WNOWAIT))

1258

return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);

1256

return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);

1259

1257

1260

retval = wo->wo_rusage

1258

retval = wo->wo_rusage

1261

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1259

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1262

if (!retval && wo->wo_stat)

1260

if (!retval && wo->wo_stat)

1263

retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);

1261

retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);

1264

1262

1265

infop = wo->wo_info;

1263

infop = wo->wo_info;

1266

if (!retval && infop)

1264

if (!retval && infop)

1267

retval = put_user(SIGCHLD, &infop->si_signo);

1265

retval = put_user(SIGCHLD, &infop->si_signo);

1268

if (!retval && infop)

1266

if (!retval && infop)

1269

retval = put_user(0, &infop->si_errno);

1267

retval = put_user(0, &infop->si_errno);

1270

if (!retval && infop)

1268

if (!retval && infop)

1271

retval = put_user((short)why, &infop->si_code);

1269

retval = put_user((short)why, &infop->si_code);

1272

if (!retval && infop)

1270

if (!retval && infop)

1273

retval = put_user(exit_code, &infop->si_status);

1271

retval = put_user(exit_code, &infop->si_status);

1274

if (!retval && infop)

1272

if (!retval && infop)

1275

retval = put_user(pid, &infop->si_pid);

1273

retval = put_user(pid, &infop->si_pid);

1276

if (!retval && infop)

1274

if (!retval && infop)

1277

retval = put_user(uid, &infop->si_uid);

1275

retval = put_user(uid, &infop->si_uid);

1278

if (!retval)

1276

if (!retval)

1279

retval = pid;

1277

retval = pid;

1280

put_task_struct(p);

1278

put_task_struct(p);

1281

1279

1282

BUG_ON(!retval);

1280

BUG_ON(!retval);

1283

return retval;

1281

return retval;

1284

}

1282

}

1285

1283

1286

/*

1284

/*

1287

* Handle do_wait work for one task in a live, non-stopped state.

1285

* Handle do_wait work for one task in a live, non-stopped state.

1288

* read_lock(&tasklist_lock) on entry. If we return zero, we still hold

1286

* read_lock(&tasklist_lock) on entry. If we return zero, we still hold

1289

* the lock and this task is uninteresting. If we return nonzero, we have

1287

* the lock and this task is uninteresting. If we return nonzero, we have

1290

* released the lock and the system call should return.

1288

* released the lock and the system call should return.

1291

*/

1289

*/

1292

static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)

1290

static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)

1293

{

1291

{

1294

int retval;

1292

int retval;

1295

pid_t pid;

1293

pid_t pid;

1296

uid_t uid;

1294

uid_t uid;

1297

1295

1298

if (!unlikely(wo->wo_flags & WCONTINUED))

1296

if (!unlikely(wo->wo_flags & WCONTINUED))

1299

return 0;

1297

return 0;

1300

1298

1301

if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))

1299

if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))

1302

return 0;

1300

return 0;

1303

1301

1304

spin_lock_irq(&p->sighand->siglock);

1302

spin_lock_irq(&p->sighand->siglock);

1305

/* Re-check with the lock held. */

1303

/* Re-check with the lock held. */

1306

if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {

1304

if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {

1307

spin_unlock_irq(&p->sighand->siglock);

1305

spin_unlock_irq(&p->sighand->siglock);

1308

return 0;

1306

return 0;

1309

}

1307

}

1310

if (!unlikely(wo->wo_flags & WNOWAIT))

1308

if (!unlikely(wo->wo_flags & WNOWAIT))

1311

p->signal->flags &= ~SIGNAL_STOP_CONTINUED;

1309

p->signal->flags &= ~SIGNAL_STOP_CONTINUED;

1312

uid = from_kuid_munged(current_user_ns(), task_uid(p));

1310

uid = from_kuid_munged(current_user_ns(), task_uid(p));

1313

spin_unlock_irq(&p->sighand->siglock);

1311

spin_unlock_irq(&p->sighand->siglock);

1314

1312

1315

pid = task_pid_vnr(p);

1313

pid = task_pid_vnr(p);

1316

get_task_struct(p);

1314

get_task_struct(p);

1317

read_unlock(&tasklist_lock);

1315

read_unlock(&tasklist_lock);

1318

1316

1319

if (!wo->wo_info) {

1317

if (!wo->wo_info) {

1320

retval = wo->wo_rusage

1318

retval = wo->wo_rusage

1321

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1319

? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

1322

put_task_struct(p);

1320

put_task_struct(p);

1323

if (!retval && wo->wo_stat)

1321

if (!retval && wo->wo_stat)

1324

retval = put_user(0xffff, wo->wo_stat);

1322

retval = put_user(0xffff, wo->wo_stat);

1325

if (!retval)

1323

if (!retval)

1326

retval = pid;

1324

retval = pid;

1327

} else {

1325

} else {

1328

retval = wait_noreap_copyout(wo, p, pid, uid,

1326

retval = wait_noreap_copyout(wo, p, pid, uid,

1329

CLD_CONTINUED, SIGCONT);

1327

CLD_CONTINUED, SIGCONT);

1330

BUG_ON(retval == 0);

1328

BUG_ON(retval == 0);

1331

}

1329

}

1332

1330

1333

return retval;

1331

return retval;

1334

}

1332

}

1335

1333

1336

/*

1334

/*

1337

* Consider @p for a wait by @parent.

1335

* Consider @p for a wait by @parent.

1338

*

1336

*

1339

* -ECHILD should be in ->notask_error before the first call.

1337

* -ECHILD should be in ->notask_error before the first call.

1340

* Returns nonzero for a final return, when we have unlocked tasklist_lock.

1338

* Returns nonzero for a final return, when we have unlocked tasklist_lock.

1341

* Returns zero if the search for a child should continue;

1339

* Returns zero if the search for a child should continue;

1342

* then ->notask_error is 0 if @p is an eligible child,

1340

* then ->notask_error is 0 if @p is an eligible child,

1343

* or another error from security_task_wait(), or still -ECHILD.

1341

* or another error from security_task_wait(), or still -ECHILD.

1344

*/

1342

*/

1345

static int wait_consider_task(struct wait_opts *wo, int ptrace,

1343

static int wait_consider_task(struct wait_opts *wo, int ptrace,

1346

struct task_struct *p)

1344

struct task_struct *p)

1347

{

1345

{

1348

int ret = eligible_child(wo, p);

1346

int ret = eligible_child(wo, p);

1349

if (!ret)

1347

if (!ret)

1350

return ret;

1348

return ret;

1351

1349

1352

ret = security_task_wait(p);

1350

ret = security_task_wait(p);

1353

if (unlikely(ret < 0)) {

1351

if (unlikely(ret < 0)) {

1354

/*

1352

/*

1355

* If we have not yet seen any eligible child,

1353

* If we have not yet seen any eligible child,

1356

* then let this error code replace -ECHILD.

1354

* then let this error code replace -ECHILD.

1357

* A permission error will give the user a clue

1355

* A permission error will give the user a clue

1358

* to look for security policy problems, rather

1356

* to look for security policy problems, rather

1359

* than for mysterious wait bugs.

1357

* than for mysterious wait bugs.

1360

*/

1358

*/

1361

if (wo->notask_error)

1359

if (wo->notask_error)

1362

wo->notask_error = ret;

1360

wo->notask_error = ret;

1363

return 0;

1361

return 0;

1364

}

1362

}

1365

1363

1366

/* dead body doesn't have much to contribute */

1364

/* dead body doesn't have much to contribute */

1367

if (unlikely(p->exit_state == EXIT_DEAD)) {

1365

if (unlikely(p->exit_state == EXIT_DEAD)) {

1368

/*

1366

/*

1369

* But do not ignore this task until the tracer does

1367

* But do not ignore this task until the tracer does

1370

* wait_task_zombie()->do_notify_parent().

1368

* wait_task_zombie()->do_notify_parent().

1371

*/

1369

*/

1372

if (likely(!ptrace) && unlikely(ptrace_reparented(p)))

1370

if (likely(!ptrace) && unlikely(ptrace_reparented(p)))

1373

wo->notask_error = 0;

1371

wo->notask_error = 0;

1374

return 0;

1372

return 0;

1375

}

1373

}

1376

1374

1377

/* slay zombie? */

1375

/* slay zombie? */

1378

if (p->exit_state == EXIT_ZOMBIE) {

1376

if (p->exit_state == EXIT_ZOMBIE) {

1379

/*

1377

/*

1380

* A zombie ptracee is only visible to its ptracer.

1378

* A zombie ptracee is only visible to its ptracer.

1381

* Notification and reaping will be cascaded to the real

1379

* Notification and reaping will be cascaded to the real

1382

* parent when the ptracer detaches.

1380

* parent when the ptracer detaches.

1383

*/

1381

*/

1384

if (likely(!ptrace) && unlikely(p->ptrace)) {

1382

if (likely(!ptrace) && unlikely(p->ptrace)) {

1385

/* it will become visible, clear notask_error */

1383

/* it will become visible, clear notask_error */

1386

wo->notask_error = 0;

1384

wo->notask_error = 0;

1387

return 0;

1385

return 0;

1388

}

1386

}

1389

1387

1390

/* we don't reap group leaders with subthreads */

1388

/* we don't reap group leaders with subthreads */

1391

if (!delay_group_leader(p))

1389

if (!delay_group_leader(p))

1392

return wait_task_zombie(wo, p);

1390

return wait_task_zombie(wo, p);

1393

1391

1394

/*

1392

/*

1395

* Allow access to stopped/continued state via zombie by

1393

* Allow access to stopped/continued state via zombie by

1396

* falling through. Clearing of notask_error is complex.

1394

* falling through. Clearing of notask_error is complex.

1397

*

1395

*

1398

* When !@ptrace:

1396

* When !@ptrace:

1399

*

1397

*

1400

* If WEXITED is set, notask_error should naturally be

1398

* If WEXITED is set, notask_error should naturally be

1401

* cleared. If not, subset of WSTOPPED|WCONTINUED is set,

1399

* cleared. If not, subset of WSTOPPED|WCONTINUED is set,

1402

* so, if there are live subthreads, there are events to

1400

* so, if there are live subthreads, there are events to

1403

* wait for. If all subthreads are dead, it's still safe

1401

* wait for. If all subthreads are dead, it's still safe

1404

* to clear - this function will be called again in finite

1402

* to clear - this function will be called again in finite

1405

* amount time once all the subthreads are released and

1403

* amount time once all the subthreads are released and

1406

* will then return without clearing.

1404

* will then return without clearing.

1407

*

1405

*

1408

* When @ptrace:

1406

* When @ptrace:

1409

*

1407

*

1410

* Stopped state is per-task and thus can't change once the

1408

* Stopped state is per-task and thus can't change once the

1411

* target task dies. Only continued and exited can happen.

1409

* target task dies. Only continued and exited can happen.

1412

* Clear notask_error if WCONTINUED | WEXITED.

1410

* Clear notask_error if WCONTINUED | WEXITED.

1413

*/

1411

*/

1414

if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))

1412

if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))

1415

wo->notask_error = 0;

1413

wo->notask_error = 0;

1416

} else {

1414

} else {

1417

/*

1415

/*

1418

* If @p is ptraced by a task in its real parent's group,

1416

* If @p is ptraced by a task in its real parent's group,

1419

* hide group stop/continued state when looking at @p as

1417

* hide group stop/continued state when looking at @p as

1420

* the real parent; otherwise, a single stop can be

1418

* the real parent; otherwise, a single stop can be

1421

* reported twice as group and ptrace stops.

1419

* reported twice as group and ptrace stops.

1422

*

1420

*

1423

* If a ptracer wants to distinguish the two events for its

1421

* If a ptracer wants to distinguish the two events for its

1424

* own children, it should create a separate process which

1422

* own children, it should create a separate process which

1425

* takes the role of real parent.

1423

* takes the role of real parent.

1426

*/

1424

*/

1427

if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))

1425

if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))

1428

return 0;

1426

return 0;

1429

1427

1430

/*

1428

/*

1431

* @p is alive and it's gonna stop, continue or exit, so

1429

* @p is alive and it's gonna stop, continue or exit, so

1432

* there always is something to wait for.

1430

* there always is something to wait for.

1433

*/

1431

*/

1434

wo->notask_error = 0;

1432

wo->notask_error = 0;

1435

}

1433

}

1436

1434

1437

/*

1435

/*

1438

* Wait for stopped. Depending on @ptrace, different stopped state

1436

* Wait for stopped. Depending on @ptrace, different stopped state

1439

* is used and the two don't interact with each other.

1437

* is used and the two don't interact with each other.

1440

*/

1438

*/

1441

ret = wait_task_stopped(wo, ptrace, p);

1439

ret = wait_task_stopped(wo, ptrace, p);

1442

if (ret)

1440

if (ret)

1443

return ret;

1441

return ret;

1444

1442

1445

/*

1443

/*

1446

* Wait for continued. There's only one continued state and the

1444

* Wait for continued. There's only one continued state and the

1447

* ptracer can consume it which can confuse the real parent. Don't

1445

* ptracer can consume it which can confuse the real parent. Don't

1448

* use WCONTINUED from ptracer. You don't need or want it.

1446

* use WCONTINUED from ptracer. You don't need or want it.

1449

*/

1447

*/

1450

return wait_task_continued(wo, p);

1448

return wait_task_continued(wo, p);

1451

}

1449

}

1452

1450

1453

/*

1451

/*

1454

* Do the work of do_wait() for one thread in the group, @tsk.

1452

* Do the work of do_wait() for one thread in the group, @tsk.

1455

*

1453

*

1456

* -ECHILD should be in ->notask_error before the first call.

1454

* -ECHILD should be in ->notask_error before the first call.

1457

* Returns nonzero for a final return, when we have unlocked tasklist_lock.

1455

* Returns nonzero for a final return, when we have unlocked tasklist_lock.

1458

* Returns zero if the search for a child should continue; then

1456

* Returns zero if the search for a child should continue; then

1459

* ->notask_error is 0 if there were any eligible children,

1457

* ->notask_error is 0 if there were any eligible children,

1460

* or another error from security_task_wait(), or still -ECHILD.

1458

* or another error from security_task_wait(), or still -ECHILD.

1461

*/

1459

*/

1462

static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)

1460

static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)

1463

{

1461

{

1464

struct task_struct *p;

1462

struct task_struct *p;

1465

1463

1466

list_for_each_entry(p, &tsk->children, sibling) {

1464

list_for_each_entry(p, &tsk->children, sibling) {

1467

int ret = wait_consider_task(wo, 0, p);

1465

int ret = wait_consider_task(wo, 0, p);

1468

if (ret)

1466

if (ret)

1469

return ret;

1467

return ret;

1470

}

1468

}

1471

1469

1472

return 0;

1470

return 0;

1473

}

1471

}

1474

1472

1475

static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)

1473

static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)

1476

{

1474

{

1477

struct task_struct *p;

1475

struct task_struct *p;

1478

1476

1479

list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {

1477

list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {

1480

int ret = wait_consider_task(wo, 1, p);

1478

int ret = wait_consider_task(wo, 1, p);

1481

if (ret)

1479

if (ret)

1482

return ret;

1480

return ret;

1483

}

1481

}

1484

1482

1485

return 0;

1483

return 0;

1486

}

1484

}

1487

1485

1488

static int child_wait_callback(wait_queue_t *wait, unsigned mode,

1486

static int child_wait_callback(wait_queue_t *wait, unsigned mode,

1489

int sync, void *key)

1487

int sync, void *key)

1490

{

1488

{

1491

struct wait_opts *wo = container_of(wait, struct wait_opts,

1489

struct wait_opts *wo = container_of(wait, struct wait_opts,

1492

child_wait);

1490

child_wait);

1493

struct task_struct *p = key;

1491

struct task_struct *p = key;

1494

1492

1495

if (!eligible_pid(wo, p))

1493

if (!eligible_pid(wo, p))

1496

return 0;

1494

return 0;

1497

1495

1498

if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)

1496

if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)

1499

return 0;

1497

return 0;

1500

1498

1501

return default_wake_function(wait, mode, sync, key);

1499

return default_wake_function(wait, mode, sync, key);

1502

}

1500

}

1503

1501

1504

void __wake_up_parent(struct task_struct *p, struct task_struct *parent)

1502

void __wake_up_parent(struct task_struct *p, struct task_struct *parent)

1505

{

1503

{

1506

__wake_up_sync_key(&parent->signal->wait_chldexit,

1504

__wake_up_sync_key(&parent->signal->wait_chldexit,

1507

TASK_INTERRUPTIBLE, 1, p);

1505

TASK_INTERRUPTIBLE, 1, p);

1508

}

1506

}

1509

1507

1510

static long do_wait(struct wait_opts *wo)

1508

static long do_wait(struct wait_opts *wo)

1511

{

1509

{

1512

struct task_struct *tsk;

1510

struct task_struct *tsk;

1513

int retval;

1511

int retval;

1514

1512

1515

trace_sched_process_wait(wo->wo_pid);

1513

trace_sched_process_wait(wo->wo_pid);

1516

1514

1517

init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);

1515

init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);

1518

wo->child_wait.private = current;

1516

wo->child_wait.private = current;

1519

add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);

1517

add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);

1520

repeat:

1518

repeat:

1521

/*

1519

/*

1522

* If there is nothing that can match our critiera just get out.

1520

* If there is nothing that can match our critiera just get out.

1523

* We will clear ->notask_error to zero if we see any child that

1521

* We will clear ->notask_error to zero if we see any child that

1524

* might later match our criteria, even if we are not able to reap

1522

* might later match our criteria, even if we are not able to reap

1525

* it yet.

1523

* it yet.

1526

*/

1524

*/

1527

wo->notask_error = -ECHILD;

1525

wo->notask_error = -ECHILD;

1528

if ((wo->wo_type < PIDTYPE_MAX) &&

1526

if ((wo->wo_type < PIDTYPE_MAX) &&

1529

(!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))

1527

(!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))

1530

goto notask;

1528

goto notask;

1531

1529

1532

set_current_state(TASK_INTERRUPTIBLE);

1530

set_current_state(TASK_INTERRUPTIBLE);

1533

read_lock(&tasklist_lock);

1531

read_lock(&tasklist_lock);

1534

tsk = current;

1532

tsk = current;

1535

do {

1533

do {

1536

retval = do_wait_thread(wo, tsk);

1534

retval = do_wait_thread(wo, tsk);

1537

if (retval)

1535

if (retval)

1538

goto end;

1536

goto end;

1539

1537

1540

retval = ptrace_do_wait(wo, tsk);

1538

retval = ptrace_do_wait(wo, tsk);

1541

if (retval)

1539

if (retval)

1542

goto end;

1540

goto end;

1543

1541

1544

if (wo->wo_flags & __WNOTHREAD)

1542

if (wo->wo_flags & __WNOTHREAD)

1545

break;

1543

break;

1546

} while_each_thread(current, tsk);

1544

} while_each_thread(current, tsk);

1547

read_unlock(&tasklist_lock);

1545

read_unlock(&tasklist_lock);

1548

1546

1549

notask:

1547

notask:

1550

retval = wo->notask_error;

1548

retval = wo->notask_error;

1551

if (!retval && !(wo->wo_flags & WNOHANG)) {

1549

if (!retval && !(wo->wo_flags & WNOHANG)) {

1552

retval = -ERESTARTSYS;

1550

retval = -ERESTARTSYS;

1553

if (!signal_pending(current)) {

1551

if (!signal_pending(current)) {

1554

schedule();

1552

schedule();

1555

goto repeat;

1553

goto repeat;

1556

}

1554

}

1557

}

1555

}

1558

end:

1556

end:

1559

__set_current_state(TASK_RUNNING);

1557

__set_current_state(TASK_RUNNING);

1560

remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);

1558

remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);

1561

return retval;

1559

return retval;

1562

}

1560

}

1563

1561

1564

SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,

1562

SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,

1565

infop, int, options, struct rusage __user *, ru)

1563

infop, int, options, struct rusage __user *, ru)

1566

{

1564

{

1567

struct wait_opts wo;

1565

struct wait_opts wo;

1568

struct pid *pid = NULL;

1566

struct pid *pid = NULL;

1569

enum pid_type type;

1567

enum pid_type type;

1570

long ret;

1568

long ret;

1571

1569

1572

if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))

1570

if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))

1573

return -EINVAL;

1571

return -EINVAL;

1574

if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))

1572

if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))

1575

return -EINVAL;

1573

return -EINVAL;

1576

1574

1577

switch (which) {

1575

switch (which) {

1578

case P_ALL:

1576

case P_ALL:

1579

type = PIDTYPE_MAX;

1577

type = PIDTYPE_MAX;

1580

break;

1578

break;

1581

case P_PID:

1579

case P_PID:

1582

type = PIDTYPE_PID;

1580

type = PIDTYPE_PID;

1583

if (upid <= 0)

1581

if (upid <= 0)

1584

return -EINVAL;

1582

return -EINVAL;

1585

break;

1583

break;

1586

case P_PGID:

1584

case P_PGID:

1587

type = PIDTYPE_PGID;

1585

type = PIDTYPE_PGID;

1588

if (upid <= 0)

1586

if (upid <= 0)

1589

return -EINVAL;

1587

return -EINVAL;

1590

break;

1588

break;

1591

default:

1589

default:

1592

return -EINVAL;

1590

return -EINVAL;

1593

}

1591

}

1594

1592

1595

if (type < PIDTYPE_MAX)

1593

if (type < PIDTYPE_MAX)

1596

pid = find_get_pid(upid);

1594

pid = find_get_pid(upid);

1597

1595

1598

wo.wo_type = type;

1596

wo.wo_type = type;

1599

wo.wo_pid = pid;

1597

wo.wo_pid = pid;

1600

wo.wo_flags = options;

1598

wo.wo_flags = options;

1601

wo.wo_info = infop;

1599

wo.wo_info = infop;

1602

wo.wo_stat = NULL;

1600

wo.wo_stat = NULL;

1603

wo.wo_rusage = ru;

1601

wo.wo_rusage = ru;

1604

ret = do_wait(&wo);

1602

ret = do_wait(&wo);

1605

1603

1606

if (ret > 0) {

1604

if (ret > 0) {

1607

ret = 0;

1605

ret = 0;

1608

} else if (infop) {

1606

} else if (infop) {

1609

/*

1607

/*

1610

* For a WNOHANG return, clear out all the fields

1608

* For a WNOHANG return, clear out all the fields

1611

* we would set so the user can easily tell the

1609

* we would set so the user can easily tell the

1612

* difference.

1610

* difference.

1613

*/

1611

*/

1614

if (!ret)

1612

if (!ret)

1615

ret = put_user(0, &infop->si_signo);

1613

ret = put_user(0, &infop->si_signo);

1616

if (!ret)

1614

if (!ret)

1617

ret = put_user(0, &infop->si_errno);

1615

ret = put_user(0, &infop->si_errno);

1618

if (!ret)

1616

if (!ret)

1619

ret = put_user(0, &infop->si_code);

1617

ret = put_user(0, &infop->si_code);

1620

if (!ret)

1618

if (!ret)

1621

ret = put_user(0, &infop->si_pid);

1619

ret = put_user(0, &infop->si_pid);

1622

if (!ret)

1620

if (!ret)

1623

ret = put_user(0, &infop->si_uid);

1621

ret = put_user(0, &infop->si_uid);

1624

if (!ret)

1622

if (!ret)

1625

ret = put_user(0, &infop->si_status);

1623

ret = put_user(0, &infop->si_status);

1626

}

1624

}

1627

1625

1628

put_pid(pid);

1626

put_pid(pid);

1629

return ret;

1627

return ret;

1630

}

1628

}

1631

1629

1632

SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,

1630

SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,

1633

int, options, struct rusage __user *, ru)

1631

int, options, struct rusage __user *, ru)

1634

{

1632

{

1635

struct wait_opts wo;

1633

struct wait_opts wo;

1636

struct pid *pid = NULL;

1634

struct pid *pid = NULL;

1637

enum pid_type type;

1635

enum pid_type type;

1638

long ret;

1636

long ret;

1639

1637

1640

if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|

1638

if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|

1641

__WNOTHREAD|__WCLONE|__WALL))

1639

__WNOTHREAD|__WCLONE|__WALL))

1642

return -EINVAL;

1640

return -EINVAL;

1643

1641

1644

if (upid == -1)

1642

if (upid == -1)

1645

type = PIDTYPE_MAX;

1643

type = PIDTYPE_MAX;

1646

else if (upid < 0) {

1644

else if (upid < 0) {

1647

type = PIDTYPE_PGID;

1645

type = PIDTYPE_PGID;

1648

pid = find_get_pid(-upid);

1646

pid = find_get_pid(-upid);

1649

} else if (upid == 0) {

1647

} else if (upid == 0) {

1650

type = PIDTYPE_PGID;

1648

type = PIDTYPE_PGID;

1651

pid = get_task_pid(current, PIDTYPE_PGID);

1649

pid = get_task_pid(current, PIDTYPE_PGID);

1652

} else /* upid > 0 */ {

1650

} else /* upid > 0 */ {

1653

type = PIDTYPE_PID;

1651

type = PIDTYPE_PID;

1654

pid = find_get_pid(upid);

1652

pid = find_get_pid(upid);

1655

}

1653

}

1656

1654

1657

wo.wo_type = type;

1655

wo.wo_type = type;

1658

wo.wo_pid = pid;

1656

wo.wo_pid = pid;

1659

wo.wo_flags = options | WEXITED;

1657

wo.wo_flags = options | WEXITED;

1660

wo.wo_info = NULL;

1658

wo.wo_info = NULL;

1661

wo.wo_stat = stat_addr;

1659

wo.wo_stat = stat_addr;

1662

wo.wo_rusage = ru;

1660

wo.wo_rusage = ru;

1663

ret = do_wait(&wo);

1661

ret = do_wait(&wo);

1664

put_pid(pid);

1662

put_pid(pid);

1665

1663

1666

return ret;

1664

return ret;

1667

}

1665

}

1668

1666

1669

#ifdef __ARCH_WANT_SYS_WAITPID

1667

#ifdef __ARCH_WANT_SYS_WAITPID

1670

1668

1671

/*

1669

/*

1672

* sys_waitpid() remains for compatibility. waitpid() should be

1670

* sys_waitpid() remains for compatibility. waitpid() should be

1673

* implemented by calling sys_wait4() from libc.a.

1671

* implemented by calling sys_wait4() from libc.a.

1674

*/

1672

*/

1675

SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)

1673

SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)

1676

{

1674

{

1677

return sys_wait4(pid, stat_addr, options, NULL);

1675

return sys_wait4(pid, stat_addr, options, NULL);

1678

}

1676

}

1679

1677

GITLAB

exit: call disassociate_ctty() before exit_task_namespaces()

 /*
  *  linux/kernel/exit.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/capability.h>
 #include <linux/completion.h>
 #include <linux/personality.h>
 #include <linux/tty.h>
 #include <linux/iocontext.h>
 #include <linux/key.h>
 #include <linux/security.h>
 #include <linux/cpu.h>
 #include <linux/acct.h>
 #include <linux/tsacct_kern.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
 #include <linux/freezer.h>
 #include <linux/binfmts.h>
 #include <linux/nsproxy.h>
 #include <linux/pid_namespace.h>
 #include <linux/ptrace.h>
 #include <linux/profile.h>
 #include <linux/mount.h>
 #include <linux/proc_fs.h>
 #include <linux/kthread.h>
 #include <linux/mempolicy.h>
 #include <linux/taskstats_kern.h>
 #include <linux/delayacct.h>
 #include <linux/cgroup.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
 #include <linux/posix-timers.h>
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
 #include <linux/futex.h>
 #include <linux/pipe_fs_i.h>
 #include <linux/audit.h> /* for audit_free() */
 #include <linux/resource.h>
 #include <linux/blkdev.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/tracehook.h>
 #include <linux/fs_struct.h>
 #include <linux/init_task.h>
 #include <linux/perf_event.h>
 #include <trace/events/sched.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/oom.h>
 #include <linux/writeback.h>
 #include <linux/shm.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
 static void exit_mm(struct task_struct * tsk);
 static void __unhash_process(struct task_struct *p, bool group_dead)
 {
 	nr_threads--;
 	detach_pid(p, PIDTYPE_PID);
 	if (group_dead) {
 		detach_pid(p, PIDTYPE_PGID);
 		detach_pid(p, PIDTYPE_SID);
 		list_del_rcu(&p->tasks);
 		list_del_init(&p->sibling);
 		__this_cpu_dec(process_counts);
 	}
 	list_del_rcu(&p->thread_group);
 	list_del_rcu(&p->thread_node);
 }
 /*
  * This function expects the tasklist_lock write-locked.
  */
 static void __exit_signal(struct task_struct *tsk)
 {
 	struct signal_struct *sig = tsk->signal;
 	bool group_dead = thread_group_leader(tsk);
 	struct sighand_struct *sighand;
 	struct tty_struct *uninitialized_var(tty);
 	cputime_t utime, stime;
 	sighand = rcu_dereference_check(tsk->sighand,
 					lockdep_tasklist_lock_is_held());
 	spin_lock(&sighand->siglock);
 	posix_cpu_timers_exit(tsk);
 	if (group_dead) {
 		posix_cpu_timers_exit_group(tsk);
 		tty = sig->tty;
 		sig->tty = NULL;
 	} else {
 		/*
 		 * This can only happen if the caller is de_thread().
 		 * FIXME: this is the temporary hack, we should teach
 		 * posix-cpu-timers to handle this case correctly.
 		 */
 		if (unlikely(has_group_leader_pid(tsk)))
 			posix_cpu_timers_exit_group(tsk);
 		/*
 		 * If there is any task waiting for the group exit
 		 * then notify it:
 		 */
 		if (sig->notify_count > 0 && !--sig->notify_count)
 			wake_up_process(sig->group_exit_task);
 		if (tsk == sig->curr_target)
 			sig->curr_target = next_thread(tsk);
 		/*
 		 * Accumulate here the counters for all threads but the
 		 * group leader as they die, so they can be added into
 		 * the process-wide totals when those are taken.
 		 * The group leader stays around as a zombie as long
 		 * as there are other threads.  When it gets reaped,
 		 * the exit.c code will add its counts into these totals.
 		 * We won't ever get here for the group leader, since it
 		 * will have been the last reference on the signal_struct.
 		 */
 		task_cputime(tsk, &utime, &stime);
 		sig->utime += utime;
 		sig->stime += stime;
 		sig->gtime += task_gtime(tsk);
 		sig->min_flt += tsk->min_flt;
 		sig->maj_flt += tsk->maj_flt;
 		sig->nvcsw += tsk->nvcsw;
 		sig->nivcsw += tsk->nivcsw;
 		sig->inblock += task_io_get_inblock(tsk);
 		sig->oublock += task_io_get_oublock(tsk);
 		task_io_accounting_add(&sig->ioac, &tsk->ioac);
 		sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
 	}
 	sig->nr_threads--;
 	__unhash_process(tsk, group_dead);
 	/*
 	 * Do this under ->siglock, we can race with another thread
 	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
 	 */
 	flush_sigqueue(&tsk->pending);
 	tsk->sighand = NULL;
 	spin_unlock(&sighand->siglock);
 	__cleanup_sighand(sighand);
 	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
 	if (group_dead) {
 		flush_sigqueue(&sig->shared_pending);
 		tty_kref_put(tty);
 	}
 }
 static void delayed_put_task_struct(struct rcu_head *rhp)
 {
 	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
 	perf_event_delayed_put(tsk);
 	trace_sched_process_free(tsk);
 	put_task_struct(tsk);
 }
 void release_task(struct task_struct * p)
 {
 	struct task_struct *leader;
 	int zap_leader;
 repeat:
 	/* don't need to get the RCU readlock here - the process is dead and
 	 * can't be modifying its own credentials. But shut RCU-lockdep up */
 	rcu_read_lock();
 	atomic_dec(&__task_cred(p)->user->processes);
 	rcu_read_unlock();
 	proc_flush_task(p);
 	write_lock_irq(&tasklist_lock);
 	ptrace_release_task(p);
 	__exit_signal(p);
 	/*
 	 * If we are the last non-leader member of the thread
 	 * group, and the leader is zombie, then notify the
 	 * group leader's parent process. (if it wants notification.)
 	 */
 	zap_leader = 0;
 	leader = p->group_leader;
 	if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
 		/*
 		 * If we were the last child thread and the leader has
 		 * exited already, and the leader's parent ignores SIGCHLD,
 		 * then we are the one who should release the leader.
 		 */
 		zap_leader = do_notify_parent(leader, leader->exit_signal);
 		if (zap_leader)
 			leader->exit_state = EXIT_DEAD;
 	}
 	write_unlock_irq(&tasklist_lock);
 	release_thread(p);
 	call_rcu(&p->rcu, delayed_put_task_struct);
 	p = leader;
 	if (unlikely(zap_leader))
 		goto repeat;
 }
 /*
  * This checks not only the pgrp, but falls back on the pid if no
  * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
  * without this...
  *
  * The caller must hold rcu lock or the tasklist lock.
  */
 struct pid *session_of_pgrp(struct pid *pgrp)
 {
 	struct task_struct *p;
 	struct pid *sid = NULL;
 	p = pid_task(pgrp, PIDTYPE_PGID);
 	if (p == NULL)
 		p = pid_task(pgrp, PIDTYPE_PID);
 	if (p != NULL)
 		sid = task_session(p);
 	return sid;
 }
 /*
  * Determine if a process group is "orphaned", according to the POSIX
  * definition in 2.2.2.52.  Orphaned process groups are not to be affected
  * by terminal-generated stop signals.  Newly orphaned process groups are
  * to receive a SIGHUP and a SIGCONT.
  *
  * "I ask you, have you ever known what it is to be an orphan?"
  */
 static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
 {
 	struct task_struct *p;
 	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
 		if ((p == ignored_task) ||
 		    (p->exit_state && thread_group_empty(p)) ||
 		    is_global_init(p->real_parent))
 			continue;
 		if (task_pgrp(p->real_parent) != pgrp &&
 		    task_session(p->real_parent) == task_session(p))
 			return 0;
 	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 	return 1;
 }
 int is_current_pgrp_orphaned(void)
 {
 	int retval;
 	read_lock(&tasklist_lock);
 	retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
 	read_unlock(&tasklist_lock);
 	return retval;
 }
 static bool has_stopped_jobs(struct pid *pgrp)
 {
 	struct task_struct *p;
 	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
 		if (p->signal->flags & SIGNAL_STOP_STOPPED)
 			return true;
 	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 	return false;
 }
 /*
  * Check to see if any process groups have become orphaned as
  * a result of our exiting, and if they have any stopped jobs,
  * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
  */
 static void
 kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
 {
 	struct pid *pgrp = task_pgrp(tsk);
 	struct task_struct *ignored_task = tsk;
 	if (!parent)
 		 /* exit: our father is in a different pgrp than
 		  * we are and we were the only connection outside.
 		  */
 		parent = tsk->real_parent;
 	else
 		/* reparent: our child is in a different pgrp than
 		 * we are, and it was the only connection outside.
 		 */
 		ignored_task = NULL;
 	if (task_pgrp(parent) != pgrp &&
 	    task_session(parent) == task_session(tsk) &&
 	    will_become_orphaned_pgrp(pgrp, ignored_task) &&
 	    has_stopped_jobs(pgrp)) {
 		__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
 		__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
 	}
 }
 /*
  * Let kernel threads use this to say that they allow a certain signal.
  * Must not be used if kthread was cloned with CLONE_SIGHAND.
  */
 int allow_signal(int sig)
 {
 	if (!valid_signal(sig) || sig < 1)
 		return -EINVAL;
 	spin_lock_irq(&current->sighand->siglock);
 	/* This is only needed for daemonize()'ed kthreads */
 	sigdelset(&current->blocked, sig);
 	/*
 	 * Kernel threads handle their own signals. Let the signal code
 	 * know it'll be handled, so that they don't get converted to
 	 * SIGKILL or just silently dropped.
 	 */
 	current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 	return 0;
 }
 EXPORT_SYMBOL(allow_signal);
 int disallow_signal(int sig)
 {
 	if (!valid_signal(sig) || sig < 1)
 		return -EINVAL;
 	spin_lock_irq(&current->sighand->siglock);
 	current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 	return 0;
 }
 EXPORT_SYMBOL(disallow_signal);
 #ifdef CONFIG_MM_OWNER
 /*
  * A task is exiting.   If it owned this mm, find a new owner for the mm.
  */
 void mm_update_next_owner(struct mm_struct *mm)
 {
 	struct task_struct *c, *g, *p = current;
 retry:
 	/*
 	 * If the exiting or execing task is not the owner, it's
 	 * someone else's problem.
 	 */
 	if (mm->owner != p)
 		return;
 	/*
 	 * The current owner is exiting/execing and there are no other
 	 * candidates.  Do not leave the mm pointing to a possibly
 	 * freed task structure.
 	 */
 	if (atomic_read(&mm->mm_users) <= 1) {
 		mm->owner = NULL;
 		return;
 	}
 	read_lock(&tasklist_lock);
 	/*
 	 * Search in the children
 	 */
 	list_for_each_entry(c, &p->children, sibling) {
 		if (c->mm == mm)
 			goto assign_new_owner;
 	}
 	/*
 	 * Search in the siblings
 	 */
 	list_for_each_entry(c, &p->real_parent->children, sibling) {
 		if (c->mm == mm)
 			goto assign_new_owner;
 	}
 	/*
 	 * Search through everything else. We should not get
 	 * here often
 	 */
 	do_each_thread(g, c) {
 		if (c->mm == mm)
 			goto assign_new_owner;
 	} while_each_thread(g, c);
 	read_unlock(&tasklist_lock);
 	/*
 	 * We found no owner yet mm_users > 1: this implies that we are
 	 * most likely racing with swapoff (try_to_unuse()) or /proc or
 	 * ptrace or page migration (get_task_mm()).  Mark owner as NULL.
 	 */
 	mm->owner = NULL;
 	return;
 assign_new_owner:
 	BUG_ON(c == p);
 	get_task_struct(c);
 	/*
 	 * The task_lock protects c->mm from changing.
 	 * We always want mm->owner->mm == mm
 	 */
 	task_lock(c);
 	/*
 	 * Delay read_unlock() till we have the task_lock()
 	 * to ensure that c does not slip away underneath us
 	 */
 	read_unlock(&tasklist_lock);
 	if (c->mm != mm) {
 		task_unlock(c);
 		put_task_struct(c);
 		goto retry;
 	}
 	mm->owner = c;
 	task_unlock(c);
 	put_task_struct(c);
 }
 #endif /* CONFIG_MM_OWNER */
 /*
  * Turn us into a lazy TLB process if we
  * aren't already..
  */
 static void exit_mm(struct task_struct * tsk)
 {
 	struct mm_struct *mm = tsk->mm;
 	struct core_state *core_state;
 	mm_release(tsk, mm);
 	if (!mm)
 		return;
 	sync_mm_rss(mm);
 	/*
 	 * Serialize with any possible pending coredump.
 	 * We must hold mmap_sem around checking core_state
 	 * and clearing tsk->mm.  The core-inducing thread
 	 * will increment ->nr_threads for each thread in the
 	 * group with ->mm != NULL.
 	 */
 	down_read(&mm->mmap_sem);
 	core_state = mm->core_state;
 	if (core_state) {
 		struct core_thread self;
 		up_read(&mm->mmap_sem);
 		self.task = tsk;
 		self.next = xchg(&core_state->dumper.next, &self);
 		/*
 		 * Implies mb(), the result of xchg() must be visible
 		 * to core_state->dumper.
 		 */
 		if (atomic_dec_and_test(&core_state->nr_threads))
 			complete(&core_state->startup);
 		for (;;) {
 			set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 			if (!self.task) /* see coredump_finish() */
 				break;
 			freezable_schedule();
 		}
 		__set_task_state(tsk, TASK_RUNNING);
 		down_read(&mm->mmap_sem);
 	}
 	atomic_inc(&mm->mm_count);
 	BUG_ON(mm != tsk->active_mm);
 	/* more a memory barrier than a real lock */
 	task_lock(tsk);
 	tsk->mm = NULL;
 	up_read(&mm->mmap_sem);
 	enter_lazy_tlb(mm, current);
 	task_unlock(tsk);
 	mm_update_next_owner(mm);
 	mmput(mm);
 }
 /*
  * When we die, we re-parent all our children, and try to:
  * 1. give them to another thread in our thread group, if such a member exists
  * 2. give it to the first ancestor process which prctl'd itself as a
  *    child_subreaper for its children (like a service manager)
  * 3. give it to the init process (PID 1) in our pid namespace
  */
 static struct task_struct *find_new_reaper(struct task_struct *father)
 	__releases(&tasklist_lock)
 	__acquires(&tasklist_lock)
 {
 	struct pid_namespace *pid_ns = task_active_pid_ns(father);
 	struct task_struct *thread;
 	thread = father;
 	while_each_thread(father, thread) {
 		if (thread->flags & PF_EXITING)
 			continue;
 		if (unlikely(pid_ns->child_reaper == father))
 			pid_ns->child_reaper = thread;
 		return thread;
 	}
 	if (unlikely(pid_ns->child_reaper == father)) {
 		write_unlock_irq(&tasklist_lock);
 		if (unlikely(pid_ns == &init_pid_ns)) {
 			panic("Attempted to kill init! exitcode=0x%08x\n",
 				father->signal->group_exit_code ?:
 					father->exit_code);
 		}
 		zap_pid_ns_processes(pid_ns);
 		write_lock_irq(&tasklist_lock);
 	} else if (father->signal->has_child_subreaper) {
 		struct task_struct *reaper;
 		/*
 		 * Find the first ancestor marked as child_subreaper.
 		 * Note that the code below checks same_thread_group(reaper,
 		 * pid_ns->child_reaper).  This is what we need to DTRT in a
 		 * PID namespace. However we still need the check above, see
 		 * http://marc.info/?l=linux-kernel&m=131385460420380
 		 */
 		for (reaper = father->real_parent;
 		     reaper != &init_task;
 		     reaper = reaper->real_parent) {
 			if (same_thread_group(reaper, pid_ns->child_reaper))
 				break;
 			if (!reaper->signal->is_child_subreaper)
 				continue;
 			thread = reaper;
 			do {
 				if (!(thread->flags & PF_EXITING))
 					return reaper;
 			} while_each_thread(reaper, thread);
 		}
 	}
 	return pid_ns->child_reaper;
 }
 /*
 * Any that need to be release_task'd are put on the @dead list.
  */
 static void reparent_leader(struct task_struct *father, struct task_struct *p,
 				struct list_head *dead)
 {
 	list_move_tail(&p->sibling, &p->real_parent->children);
 	/*
 	 * If this is a threaded reparent there is no need to
 	 * notify anyone anything has happened.
 	 */
 	if (same_thread_group(p->real_parent, father))
 		return;
 	/*
 	 * We don't want people slaying init.
 	 *
 	 * Note: we do this even if it is EXIT_DEAD, wait_task_zombie()
 	 * can change ->exit_state to EXIT_ZOMBIE. If this is the final
 	 * state, do_notify_parent() was already called and ->exit_signal
 	 * doesn't matter.
 	 */
 	p->exit_signal = SIGCHLD;
 	if (p->exit_state == EXIT_DEAD)
 		return;
 	/* If it has exited notify the new parent about this child's death. */
 	if (!p->ptrace &&
 	    p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
 		if (do_notify_parent(p, p->exit_signal)) {
 			p->exit_state = EXIT_DEAD;
 			list_move_tail(&p->sibling, dead);
 		}
 	}
 	kill_orphaned_pgrp(p, father);
 }
 static void forget_original_parent(struct task_struct *father)
 {
 	struct task_struct *p, *n, *reaper;
 	LIST_HEAD(dead_children);
 	write_lock_irq(&tasklist_lock);
 	/*
 	 * Note that exit_ptrace() and find_new_reaper() might
 	 * drop tasklist_lock and reacquire it.
 	 */
 	exit_ptrace(father);
 	reaper = find_new_reaper(father);
 	list_for_each_entry_safe(p, n, &father->children, sibling) {
 		struct task_struct *t = p;
 		do {
 			t->real_parent = reaper;
 			if (t->parent == father) {
 				BUG_ON(t->ptrace);
 				t->parent = t->real_parent;
 			}
 			if (t->pdeath_signal)
 				group_send_sig_info(t->pdeath_signal,
 						    SEND_SIG_NOINFO, t);
 		} while_each_thread(p, t);
 		reparent_leader(father, p, &dead_children);
 	}
 	write_unlock_irq(&tasklist_lock);
 	BUG_ON(!list_empty(&father->children));
 	list_for_each_entry_safe(p, n, &dead_children, sibling) {
 		list_del_init(&p->sibling);
 		release_task(p);
 	}
 }
 /*
  * Send signals to all our closest relatives so that they know
  * to properly mourn us..
  */
 static void exit_notify(struct task_struct *tsk, int group_dead)
 {
 	bool autoreap;
 	/*
 	 * This does two things:
 	 *
   	 * A.  Make init inherit all the child processes
 	 * B.  Check to see if any process groups have become orphaned
 	 *	as a result of our exiting, and if they have any stopped
 	 *	jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
 	 */
 	forget_original_parent(tsk);
 	write_lock_irq(&tasklist_lock);
 	if (group_dead)
 		kill_orphaned_pgrp(tsk->group_leader, NULL);
 	if (unlikely(tsk->ptrace)) {
 		int sig = thread_group_leader(tsk) &&
 				thread_group_empty(tsk) &&
 				!ptrace_reparented(tsk) ?
 			tsk->exit_signal : SIGCHLD;
 		autoreap = do_notify_parent(tsk, sig);
 	} else if (thread_group_leader(tsk)) {
 		autoreap = thread_group_empty(tsk) &&
 			do_notify_parent(tsk, tsk->exit_signal);
 	} else {
 		autoreap = true;
 	}
 	tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
 	/* mt-exec, de_thread() is waiting for group leader */
 	if (unlikely(tsk->signal->notify_count < 0))
 		wake_up_process(tsk->signal->group_exit_task);
 	write_unlock_irq(&tasklist_lock);
 	/* If the process is dead, release it - nobody will wait for it */
 	if (autoreap)
 		release_task(tsk);
 }
 #ifdef CONFIG_DEBUG_STACK_USAGE
 static void check_stack_usage(void)
 {
 	static DEFINE_SPINLOCK(low_water_lock);
 	static int lowest_to_date = THREAD_SIZE;
 	unsigned long free;
 	free = stack_not_used(current);
 	if (free >= lowest_to_date)
 		return;
 	spin_lock(&low_water_lock);
 	if (free < lowest_to_date) {
 		printk(KERN_WARNING "%s (%d) used greatest stack depth: "
 				"%lu bytes left\n",
 				current->comm, task_pid_nr(current), free);
 		lowest_to_date = free;
 	}
 	spin_unlock(&low_water_lock);
 }
 #else
 static inline void check_stack_usage(void) {}
 #endif
 void do_exit(long code)
 {
 	struct task_struct *tsk = current;
 	int group_dead;
 	profile_task_exit(tsk);
 	WARN_ON(blk_needs_flush_plug(tsk));
 	if (unlikely(in_interrupt()))
 		panic("Aiee, killing interrupt handler!");
 	if (unlikely(!tsk->pid))
 		panic("Attempted to kill the idle task!");
 	/*
 	 * If do_exit is called because this processes oopsed, it's possible
 	 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
 	 * continuing. Amongst other possible reasons, this is to prevent
 	 * mm_release()->clear_child_tid() from writing to a user-controlled
 	 * kernel address.
 	 */
 	set_fs(USER_DS);
 	ptrace_event(PTRACE_EVENT_EXIT, code);
 	validate_creds_for_do_exit(tsk);
 	/*
 	 * We're taking recursive faults here in do_exit. Safest is to just
 	 * leave this task alone and wait for reboot.
 	 */
 	if (unlikely(tsk->flags & PF_EXITING)) {
 		printk(KERN_ALERT
 			"Fixing recursive fault but reboot is needed!\n");
 		/*
 		 * We can do this unlocked here. The futex code uses
 		 * this flag just to verify whether the pi state
 		 * cleanup has been done or not. In the worst case it
 		 * loops once more. We pretend that the cleanup was
 		 * done as there is no way to return. Either the
 		 * OWNER_DIED bit is set by now or we push the blocked
 		 * task into the wait for ever nirwana as well.
 		 */
 		tsk->flags |= PF_EXITPIDONE;
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		schedule();
 	}
 	exit_signals(tsk);  /* sets PF_EXITING */
 	/*
 	 * tsk->flags are checked in the futex code to protect against
 	 * an exiting task cleaning up the robust pi futexes.
 	 */
 	smp_mb();
 	raw_spin_unlock_wait(&tsk->pi_lock);
 	if (unlikely(in_atomic()))
 		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
 				current->comm, task_pid_nr(current),
 				preempt_count());
 	acct_update_integrals(tsk);
 	/* sync mm's RSS info before statistics gathering */
 	if (tsk->mm)
 		sync_mm_rss(tsk->mm);
 	group_dead = atomic_dec_and_test(&tsk->signal->live);
 	if (group_dead) {
 		hrtimer_cancel(&tsk->signal->real_timer);
 		exit_itimers(tsk->signal);
 		if (tsk->mm)
 			setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
 	}
 	acct_collect(code, group_dead);
 	if (group_dead)
 		tty_audit_exit();
 	audit_free(tsk);
 	tsk->exit_code = code;
 	taskstats_exit(tsk, group_dead);
 	exit_mm(tsk);
 	if (group_dead)
 		acct_process();
 	trace_sched_process_exit(tsk);
 	exit_sem(tsk);
 	exit_shm(tsk);
 	exit_files(tsk);
 	exit_fs(tsk);
+	if (group_dead)
+		disassociate_ctty(1);
 	exit_task_namespaces(tsk);
 	exit_task_work(tsk);
 	check_stack_usage();
 	exit_thread();
 	/*
 	 * Flush inherited counters to the parent - before the parent
 	 * gets woken up by child-exit notifications.
 	 *
 	 * because of cgroup mode, must be called before cgroup_exit()
 	 */
 	perf_event_exit_task(tsk);
 	cgroup_exit(tsk, 1);
-	if (group_dead)
-		disassociate_ctty(1);
 	module_put(task_thread_info(tsk)->exec_domain->module);
 	proc_exit_connector(tsk);
 	/*
 	 * FIXME: do that only when needed, using sched_exit tracepoint
 	 */
 	flush_ptrace_hw_breakpoint(tsk);
 	exit_notify(tsk, group_dead);
 #ifdef CONFIG_NUMA
 	task_lock(tsk);
 	mpol_put(tsk->mempolicy);
 	tsk->mempolicy = NULL;
 	task_unlock(tsk);
 #endif
 #ifdef CONFIG_FUTEX
 	if (unlikely(current->pi_state_cache))
 		kfree(current->pi_state_cache);
 #endif
 	/*
 	 * Make sure we are holding no locks:
 	 */
 	debug_check_no_locks_held();
 	/*
 	 * We can do this unlocked here. The futex code uses this flag
 	 * just to verify whether the pi state cleanup has been done
 	 * or not. In the worst case it loops once more.
 	 */
 	tsk->flags |= PF_EXITPIDONE;
 	if (tsk->io_context)
 		exit_io_context(tsk);
 	if (tsk->splice_pipe)
 		free_pipe_info(tsk->splice_pipe);
 	if (tsk->task_frag.page)
 		put_page(tsk->task_frag.page);
 	validate_creds_for_do_exit(tsk);
 	preempt_disable();
 	if (tsk->nr_dirtied)
 		__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
 	exit_rcu();
 	/*
 	 * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
 	 * when the following two conditions become true.
 	 *   - There is race condition of mmap_sem (It is acquired by
 	 *     exit_mm()), and
 	 *   - SMI occurs before setting TASK_RUNINNG.
 	 *     (or hypervisor of virtual machine switches to other guest)
 	 *  As a result, we may become TASK_RUNNING after becoming TASK_DEAD
 	 *
 	 * To avoid it, we have to wait for releasing tsk->pi_lock which
 	 * is held by try_to_wake_up()
 	 */
 	smp_mb();
 	raw_spin_unlock_wait(&tsk->pi_lock);
 	/* causes final put_task_struct in finish_task_switch(). */
 	tsk->state = TASK_DEAD;
 	tsk->flags |= PF_NOFREEZE;	/* tell freezer to ignore us */
 	schedule();
 	BUG();
 	/* Avoid "noreturn function does return".  */
 	for (;;)
 		cpu_relax();	/* For when BUG is null */
 }
 EXPORT_SYMBOL_GPL(do_exit);
 void complete_and_exit(struct completion *comp, long code)
 {
 	if (comp)
 		complete(comp);
 	do_exit(code);
 }
 EXPORT_SYMBOL(complete_and_exit);
 SYSCALL_DEFINE1(exit, int, error_code)
 {
 	do_exit((error_code&0xff)<<8);
 }
 /*
  * Take down every thread in the group.  This is called by fatal signals
  * as well as by sys_exit_group (below).
  */
 void
 do_group_exit(int exit_code)
 {
 	struct signal_struct *sig = current->signal;
 	BUG_ON(exit_code & 0x80); /* core dumps don't get here */
 	if (signal_group_exit(sig))
 		exit_code = sig->group_exit_code;
 	else if (!thread_group_empty(current)) {
 		struct sighand_struct *const sighand = current->sighand;
 		spin_lock_irq(&sighand->siglock);
 		if (signal_group_exit(sig))
 			/* Another thread got here before we took the lock.  */
 			exit_code = sig->group_exit_code;
 		else {
 			sig->group_exit_code = exit_code;
 			sig->flags = SIGNAL_GROUP_EXIT;
 			zap_other_threads(current);
 		}
 		spin_unlock_irq(&sighand->siglock);
 	}
 	do_exit(exit_code);
 	/* NOTREACHED */
 }
 /*
  * this kills every thread in the thread group. Note that any externally
  * wait4()-ing process will get the correct exit code - even if this
  * thread is not the thread group leader.
  */
 SYSCALL_DEFINE1(exit_group, int, error_code)
 {
 	do_group_exit((error_code & 0xff) << 8);
 	/* NOTREACHED */
 	return 0;
 }
 struct wait_opts {
 	enum pid_type		wo_type;
 	int			wo_flags;
 	struct pid		*wo_pid;
 	struct siginfo __user	*wo_info;
 	int __user		*wo_stat;
 	struct rusage __user	*wo_rusage;
 	wait_queue_t		child_wait;
 	int			notask_error;
 };
 static inline
 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
 {
 	if (type != PIDTYPE_PID)
 		task = task->group_leader;
 	return task->pids[type].pid;
 }
 static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
 {
 	return	wo->wo_type == PIDTYPE_MAX ||
 		task_pid_type(p, wo->wo_type) == wo->wo_pid;
 }
 static int eligible_child(struct wait_opts *wo, struct task_struct *p)
 {
 	if (!eligible_pid(wo, p))
 		return 0;
 	/* Wait for all children (clone and not) if __WALL is set;
 	 * otherwise, wait for clone children *only* if __WCLONE is
 	 * set; otherwise, wait for non-clone children *only*.  (Note:
 	 * A "clone" child here is one that reports to its parent
 	 * using a signal other than SIGCHLD.) */
 	if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
 	    && !(wo->wo_flags & __WALL))
 		return 0;
 	return 1;
 }
 static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
 				pid_t pid, uid_t uid, int why, int status)
 {
 	struct siginfo __user *infop;
 	int retval = wo->wo_rusage
 		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
 	put_task_struct(p);
 	infop = wo->wo_info;
 	if (infop) {
 		if (!retval)
 			retval = put_user(SIGCHLD, &infop->si_signo);
 		if (!retval)
 			retval = put_user(0, &infop->si_errno);
 		if (!retval)
 			retval = put_user((short)why, &infop->si_code);
 		if (!retval)
 			retval = put_user(pid, &infop->si_pid);
 		if (!retval)
 			retval = put_user(uid, &infop->si_uid);
 		if (!retval)
 			retval = put_user(status, &infop->si_status);
 	}
 	if (!retval)
 		retval = pid;
 	return retval;
 }
 /*
  * Handle sys_wait4 work for one task in state EXIT_ZOMBIE.  We hold
  * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
  * the lock and this task is uninteresting.  If we return nonzero, we have
  * released the lock and the system call should return.
  */
 static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 {
 	unsigned long state;
 	int retval, status, traced;
 	pid_t pid = task_pid_vnr(p);
 	uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
 	struct siginfo __user *infop;
 	if (!likely(wo->wo_flags & WEXITED))
 		return 0;
 	if (unlikely(wo->wo_flags & WNOWAIT)) {
 		int exit_code = p->exit_code;
 		int why;
 		get_task_struct(p);
 		read_unlock(&tasklist_lock);
 		if ((exit_code & 0x7f) == 0) {
 			why = CLD_EXITED;
 			status = exit_code >> 8;
 		} else {
 			why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
 			status = exit_code & 0x7f;
 		}
 		return wait_noreap_copyout(wo, p, pid, uid, why, status);
 	}
 	/*
 	 * Try to move the task's state to DEAD
 	 * only one thread is allowed to do this:
 	 */
 	state = xchg(&p->exit_state, EXIT_DEAD);
 	if (state != EXIT_ZOMBIE) {
 		BUG_ON(state != EXIT_DEAD);
 		return 0;
 	}
 	traced = ptrace_reparented(p);
 	/*
 	 * It can be ptraced but not reparented, check
 	 * thread_group_leader() to filter out sub-threads.
 	 */
 	if (likely(!traced) && thread_group_leader(p)) {
 		struct signal_struct *psig;
 		struct signal_struct *sig;
 		unsigned long maxrss;
 		cputime_t tgutime, tgstime;
 		/*
 		 * The resource counters for the group leader are in its
 		 * own task_struct.  Those for dead threads in the group
 		 * are in its signal_struct, as are those for the child
 		 * processes it has previously reaped.  All these
 		 * accumulate in the parent's signal_struct c* fields.
 		 *
 		 * We don't bother to take a lock here to protect these
 		 * p->signal fields, because they are only touched by
 		 * __exit_signal, which runs with tasklist_lock
 		 * write-locked anyway, and so is excluded here.  We do
 		 * need to protect the access to parent->signal fields,
 		 * as other threads in the parent group can be right
 		 * here reaping other children at the same time.
 		 *
 		 * We use thread_group_cputime_adjusted() to get times for the thread
 		 * group, which consolidates times for all threads in the
 		 * group including the group leader.
 		 */
 		thread_group_cputime_adjusted(p, &tgutime, &tgstime);
 		spin_lock_irq(&p->real_parent->sighand->siglock);
 		psig = p->real_parent->signal;
 		sig = p->signal;
 		psig->cutime += tgutime + sig->cutime;
 		psig->cstime += tgstime + sig->cstime;
 		psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
 		psig->cmin_flt +=
 			p->min_flt + sig->min_flt + sig->cmin_flt;
 		psig->cmaj_flt +=
 			p->maj_flt + sig->maj_flt + sig->cmaj_flt;
 		psig->cnvcsw +=
 			p->nvcsw + sig->nvcsw + sig->cnvcsw;
 		psig->cnivcsw +=
 			p->nivcsw + sig->nivcsw + sig->cnivcsw;
 		psig->cinblock +=
 			task_io_get_inblock(p) +
 			sig->inblock + sig->cinblock;
 		psig->coublock +=
 			task_io_get_oublock(p) +
 			sig->oublock + sig->coublock;
 		maxrss = max(sig->maxrss, sig->cmaxrss);
 		if (psig->cmaxrss < maxrss)
 			psig->cmaxrss = maxrss;
 		task_io_accounting_add(&psig->ioac, &p->ioac);
 		task_io_accounting_add(&psig->ioac, &sig->ioac);
 		spin_unlock_irq(&p->real_parent->sighand->siglock);
 	}
 	/*
 	 * Now we are sure this task is interesting, and no other
 	 * thread can reap it because we set its state to EXIT_DEAD.
 	 */
 	read_unlock(&tasklist_lock);
 	retval = wo->wo_rusage
 		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
 	status = (p->signal->flags & SIGNAL_GROUP_EXIT)
 		? p->signal->group_exit_code : p->exit_code;
 	if (!retval && wo->wo_stat)
 		retval = put_user(status, wo->wo_stat);
 	infop = wo->wo_info;
 	if (!retval && infop)
 		retval = put_user(SIGCHLD, &infop->si_signo);
 	if (!retval && infop)
 		retval = put_user(0, &infop->si_errno);
 	if (!retval && infop) {
 		int why;
 		if ((status & 0x7f) == 0) {
 			why = CLD_EXITED;
 			status >>= 8;
 		} else {
 			why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
 			status &= 0x7f;
 		}
 		retval = put_user((short)why, &infop->si_code);
 		if (!retval)
 			retval = put_user(status, &infop->si_status);
 	}
 	if (!retval && infop)
 		retval = put_user(pid, &infop->si_pid);
 	if (!retval && infop)
 		retval = put_user(uid, &infop->si_uid);
 	if (!retval)
 		retval = pid;
 	if (traced) {
 		write_lock_irq(&tasklist_lock);
 		/* We dropped tasklist, ptracer could die and untrace */
 		ptrace_unlink(p);
 		/*
 		 * If this is not a sub-thread, notify the parent.
 		 * If parent wants a zombie, don't release it now.
 		 */
 		if (thread_group_leader(p) &&
 		    !do_notify_parent(p, p->exit_signal)) {
 			p->exit_state = EXIT_ZOMBIE;
 			p = NULL;
 		}
 		write_unlock_irq(&tasklist_lock);
 	}
 	if (p != NULL)
 		release_task(p);
 	return retval;
 }
 static int *task_stopped_code(struct task_struct *p, bool ptrace)
 {
 	if (ptrace) {
 		if (task_is_stopped_or_traced(p) &&
 		    !(p->jobctl & JOBCTL_LISTENING))
 			return &p->exit_code;
 	} else {
 		if (p->signal->flags & SIGNAL_STOP_STOPPED)
 			return &p->signal->group_exit_code;
 	}
 	return NULL;
 }
 /**
  * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
  * @wo: wait options
  * @ptrace: is the wait for ptrace
  * @p: task to wait for
  *
  * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
  *
  * CONTEXT:
  * read_lock(&tasklist_lock), which is released if return value is
  * non-zero.  Also, grabs and releases @p->sighand->siglock.
  *
  * RETURNS:
  * 0 if wait condition didn't exist and search for other wait conditions
  * should continue.  Non-zero return, -errno on failure and @p's pid on
  * success, implies that tasklist_lock is released and wait condition
  * search should terminate.
  */
 static int wait_task_stopped(struct wait_opts *wo,
 				int ptrace, struct task_struct *p)
 {
 	struct siginfo __user *infop;
 	int retval, exit_code, *p_code, why;
 	uid_t uid = 0; /* unneeded, required by compiler */
 	pid_t pid;
 	/*
 	 * Traditionally we see ptrace'd stopped tasks regardless of options.
 	 */
 	if (!ptrace && !(wo->wo_flags & WUNTRACED))
 		return 0;
 	if (!task_stopped_code(p, ptrace))
 		return 0;
 	exit_code = 0;
 	spin_lock_irq(&p->sighand->siglock);
 	p_code = task_stopped_code(p, ptrace);
 	if (unlikely(!p_code))
 		goto unlock_sig;
 	exit_code = *p_code;
 	if (!exit_code)
 		goto unlock_sig;
 	if (!unlikely(wo->wo_flags & WNOWAIT))
 		*p_code = 0;
 	uid = from_kuid_munged(current_user_ns(), task_uid(p));
 unlock_sig:
 	spin_unlock_irq(&p->sighand->siglock);
 	if (!exit_code)
 		return 0;
 	/*
 	 * Now we are pretty sure this task is interesting.
 	 * Make sure it doesn't get reaped out from under us while we
 	 * give up the lock and then examine it below.  We don't want to
 	 * keep holding onto the tasklist_lock while we call getrusage and
 	 * possibly take page faults for user memory.
 	 */
 	get_task_struct(p);
 	pid = task_pid_vnr(p);
 	why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
 	read_unlock(&tasklist_lock);
 	if (unlikely(wo->wo_flags & WNOWAIT))
 		return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
 	retval = wo->wo_rusage
 		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
 	if (!retval && wo->wo_stat)
 		retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);
 	infop = wo->wo_info;
 	if (!retval && infop)
 		retval = put_user(SIGCHLD, &infop->si_signo);
 	if (!retval && infop)
 		retval = put_user(0, &infop->si_errno);
 	if (!retval && infop)
 		retval = put_user((short)why, &infop->si_code);
 	if (!retval && infop)
 		retval = put_user(exit_code, &infop->si_status);
 	if (!retval && infop)
 		retval = put_user(pid, &infop->si_pid);
 	if (!retval && infop)
 		retval = put_user(uid, &infop->si_uid);
 	if (!retval)
 		retval = pid;
 	put_task_struct(p);
 	BUG_ON(!retval);
 	return retval;
 }
 /*
  * Handle do_wait work for one task in a live, non-stopped state.
  * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
  * the lock and this task is uninteresting.  If we return nonzero, we have
  * released the lock and the system call should return.
  */
 static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
 {
 	int retval;
 	pid_t pid;
 	uid_t uid;
 	if (!unlikely(wo->wo_flags & WCONTINUED))
 		return 0;
 	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
 		return 0;
 	spin_lock_irq(&p->sighand->siglock);
 	/* Re-check with the lock held.  */
 	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
 		spin_unlock_irq(&p->sighand->siglock);
 		return 0;
 	}
 	if (!unlikely(wo->wo_flags & WNOWAIT))
 		p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
 	uid = from_kuid_munged(current_user_ns(), task_uid(p));
 	spin_unlock_irq(&p->sighand->siglock);
 	pid = task_pid_vnr(p);
 	get_task_struct(p);
 	read_unlock(&tasklist_lock);
 	if (!wo->wo_info) {
 		retval = wo->wo_rusage
 			? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
 		put_task_struct(p);
 		if (!retval && wo->wo_stat)
 			retval = put_user(0xffff, wo->wo_stat);
 		if (!retval)
 			retval = pid;
 	} else {
 		retval = wait_noreap_copyout(wo, p, pid, uid,
 					     CLD_CONTINUED, SIGCONT);
 		BUG_ON(retval == 0);
 	}
 	return retval;
 }
 /*
  * Consider @p for a wait by @parent.
  *
  * -ECHILD should be in ->notask_error before the first call.
  * Returns nonzero for a final return, when we have unlocked tasklist_lock.
  * Returns zero if the search for a child should continue;
  * then ->notask_error is 0 if @p is an eligible child,
  * or another error from security_task_wait(), or still -ECHILD.
  */
 static int wait_consider_task(struct wait_opts *wo, int ptrace,
 				struct task_struct *p)
 {
 	int ret = eligible_child(wo, p);
 	if (!ret)
 		return ret;
 	ret = security_task_wait(p);
 	if (unlikely(ret < 0)) {
 		/*
 		 * If we have not yet seen any eligible child,
 		 * then let this error code replace -ECHILD.
 		 * A permission error will give the user a clue
 		 * to look for security policy problems, rather
 		 * than for mysterious wait bugs.
 		 */
 		if (wo->notask_error)
 			wo->notask_error = ret;
 		return 0;
 	}
 	/* dead body doesn't have much to contribute */
 	if (unlikely(p->exit_state == EXIT_DEAD)) {
 		/*
 		 * But do not ignore this task until the tracer does
 		 * wait_task_zombie()->do_notify_parent().
 		 */
 		if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
 			wo->notask_error = 0;
 		return 0;
 	}
 	/* slay zombie? */
 	if (p->exit_state == EXIT_ZOMBIE) {
 		/*
 		 * A zombie ptracee is only visible to its ptracer.
 		 * Notification and reaping will be cascaded to the real
 		 * parent when the ptracer detaches.
 		 */
 		if (likely(!ptrace) && unlikely(p->ptrace)) {
 			/* it will become visible, clear notask_error */
 			wo->notask_error = 0;
 			return 0;
 		}
 		/* we don't reap group leaders with subthreads */
 		if (!delay_group_leader(p))
 			return wait_task_zombie(wo, p);
 		/*
 		 * Allow access to stopped/continued state via zombie by
 		 * falling through.  Clearing of notask_error is complex.
 		 *
 		 * When !@ptrace:
 		 *
 		 * If WEXITED is set, notask_error should naturally be
 		 * cleared.  If not, subset of WSTOPPED|WCONTINUED is set,
 		 * so, if there are live subthreads, there are events to
 		 * wait for.  If all subthreads are dead, it's still safe
 		 * to clear - this function will be called again in finite
 		 * amount time once all the subthreads are released and
 		 * will then return without clearing.
 		 *
 		 * When @ptrace:
 		 *
 		 * Stopped state is per-task and thus can't change once the
 		 * target task dies.  Only continued and exited can happen.
 		 * Clear notask_error if WCONTINUED | WEXITED.
 		 */
 		if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
 			wo->notask_error = 0;
 	} else {
 		/*
 		 * If @p is ptraced by a task in its real parent's group,
 		 * hide group stop/continued state when looking at @p as
 		 * the real parent; otherwise, a single stop can be
 		 * reported twice as group and ptrace stops.
 		 *
 		 * If a ptracer wants to distinguish the two events for its
 		 * own children, it should create a separate process which
 		 * takes the role of real parent.
 		 */
 		if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))
 			return 0;
 		/*
 		 * @p is alive and it's gonna stop, continue or exit, so
 		 * there always is something to wait for.
 		 */
 		wo->notask_error = 0;
 	}
 	/*
 	 * Wait for stopped.  Depending on @ptrace, different stopped state
 	 * is used and the two don't interact with each other.
 	 */
 	ret = wait_task_stopped(wo, ptrace, p);
 	if (ret)
 		return ret;
 	/*
 	 * Wait for continued.  There's only one continued state and the
 	 * ptracer can consume it which can confuse the real parent.  Don't
 	 * use WCONTINUED from ptracer.  You don't need or want it.
 	 */
 	return wait_task_continued(wo, p);
 }
 /*
  * Do the work of do_wait() for one thread in the group, @tsk.
  *
  * -ECHILD should be in ->notask_error before the first call.
  * Returns nonzero for a final return, when we have unlocked tasklist_lock.
  * Returns zero if the search for a child should continue; then
  * ->notask_error is 0 if there were any eligible children,
  * or another error from security_task_wait(), or still -ECHILD.
  */
 static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
 {
 	struct task_struct *p;
 	list_for_each_entry(p, &tsk->children, sibling) {
 		int ret = wait_consider_task(wo, 0, p);
 		if (ret)
 			return ret;
 	}
 	return 0;
 }
 static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
 {
 	struct task_struct *p;
 	list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
 		int ret = wait_consider_task(wo, 1, p);
 		if (ret)
 			return ret;
 	}
 	return 0;
 }
 static int child_wait_callback(wait_queue_t *wait, unsigned mode,
 				int sync, void *key)
 {
 	struct wait_opts *wo = container_of(wait, struct wait_opts,
 						child_wait);
 	struct task_struct *p = key;
 	if (!eligible_pid(wo, p))
 		return 0;
 	if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
 		return 0;
 	return default_wake_function(wait, mode, sync, key);
 }
 void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
 {
 	__wake_up_sync_key(&parent->signal->wait_chldexit,
 				TASK_INTERRUPTIBLE, 1, p);
 }
 static long do_wait(struct wait_opts *wo)
 {
 	struct task_struct *tsk;
 	int retval;
 	trace_sched_process_wait(wo->wo_pid);
 	init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
 	wo->child_wait.private = current;
 	add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
 repeat:
 	/*
 	 * If there is nothing that can match our critiera just get out.
 	 * We will clear ->notask_error to zero if we see any child that
 	 * might later match our criteria, even if we are not able to reap
 	 * it yet.
 	 */
 	wo->notask_error = -ECHILD;
 	if ((wo->wo_type < PIDTYPE_MAX) &&
 	   (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
 		goto notask;
 	set_current_state(TASK_INTERRUPTIBLE);
 	read_lock(&tasklist_lock);
 	tsk = current;
 	do {
 		retval = do_wait_thread(wo, tsk);
 		if (retval)
 			goto end;
 		retval = ptrace_do_wait(wo, tsk);
 		if (retval)
 			goto end;
 		if (wo->wo_flags & __WNOTHREAD)
 			break;
 	} while_each_thread(current, tsk);
 	read_unlock(&tasklist_lock);
 notask:
 	retval = wo->notask_error;
 	if (!retval && !(wo->wo_flags & WNOHANG)) {
 		retval = -ERESTARTSYS;
 		if (!signal_pending(current)) {
 			schedule();
 			goto repeat;
 		}
 	}
 end:
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
 	return retval;
 }
 SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
 		infop, int, options, struct rusage __user *, ru)
 {
 	struct wait_opts wo;
 	struct pid *pid = NULL;
 	enum pid_type type;
 	long ret;
 	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
 		return -EINVAL;
 	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
 		return -EINVAL;
 	switch (which) {
 	case P_ALL:
 		type = PIDTYPE_MAX;
 		break;
 	case P_PID:
 		type = PIDTYPE_PID;
 		if (upid <= 0)
 			return -EINVAL;
 		break;
 	case P_PGID:
 		type = PIDTYPE_PGID;
 		if (upid <= 0)
 			return -EINVAL;
 		break;
 	default:
 		return -EINVAL;
 	}
 	if (type < PIDTYPE_MAX)
 		pid = find_get_pid(upid);
 	wo.wo_type	= type;
 	wo.wo_pid	= pid;
 	wo.wo_flags	= options;
 	wo.wo_info	= infop;
 	wo.wo_stat	= NULL;
 	wo.wo_rusage	= ru;
 	ret = do_wait(&wo);
 	if (ret > 0) {
 		ret = 0;
 	} else if (infop) {
 		/*
 		 * For a WNOHANG return, clear out all the fields
 		 * we would set so the user can easily tell the
 		 * difference.
 		 */
 		if (!ret)
 			ret = put_user(0, &infop->si_signo);
 		if (!ret)
 			ret = put_user(0, &infop->si_errno);
 		if (!ret)
 			ret = put_user(0, &infop->si_code);
 		if (!ret)
 			ret = put_user(0, &infop->si_pid);
 		if (!ret)
 			ret = put_user(0, &infop->si_uid);
 		if (!ret)
 			ret = put_user(0, &infop->si_status);
 	}
 	put_pid(pid);
 	return ret;
 }
 SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
 		int, options, struct rusage __user *, ru)
 {
 	struct wait_opts wo;
 	struct pid *pid = NULL;
 	enum pid_type type;
 	long ret;
 	if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
 			__WNOTHREAD|__WCLONE|__WALL))
 		return -EINVAL;
 	if (upid == -1)
 		type = PIDTYPE_MAX;
 	else if (upid < 0) {
 		type = PIDTYPE_PGID;
 		pid = find_get_pid(-upid);
 	} else if (upid == 0) {
 		type = PIDTYPE_PGID;
 		pid = get_task_pid(current, PIDTYPE_PGID);
 	} else /* upid > 0 */ {
 		type = PIDTYPE_PID;
 		pid = find_get_pid(upid);
 	}
 	wo.wo_type	= type;
 	wo.wo_pid	= pid;
 	wo.wo_flags	= options | WEXITED;
 	wo.wo_info	= NULL;
 	wo.wo_stat	= stat_addr;
 	wo.wo_rusage	= ru;
 	ret = do_wait(&wo);
 	put_pid(pid);
 	return ret;
 }
 #ifdef __ARCH_WANT_SYS_WAITPID
 /*
  * sys_waitpid() remains for compatibility. waitpid() should be
  * implemented by calling sys_wait4() from libc.a.
  */
 SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
 {
 	return sys_wait4(pid, stat_addr, options, NULL);
 }