ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up()

Cleanup and preparation for the next change. signal_wake_up(resume => true) is overused. None of ptrace/jctl callers actually want to wakeup a TASK_WAKEKILL task, but they can't specify the necessary mask. Turn signal_wake_up() into signal_wake_up_state(state), reintroduce signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up() which adds __TASK_TRACED. This way ptrace_signal_wake_up() can work "inside" ptrace_request() even if the tracee doesn't have the TASK_WAKEKILL bit set. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up()
Cleanup and preparation for the next change. signal_wake_up(resume => true) is overused. None of ptrace/jctl callers actually want to wakeup a TASK_WAKEKILL task, but they can't specify the necessary mask. Turn signal_wake_up() into signal_wake_up_state(state), reintroduce signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up() which adds __TASK_TRACED. This way ptrace_signal_wake_up() can work "inside" ptrace_request() even if the tracee doesn't have the TASK_WAKEKILL bit set. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov · Linus Torvalds
1 parent 9a9284153d
Showing 3 changed files with 18 additions and 15 deletions Side-by-side Diff
include/linux/sched.h
kernel/ptrace.c
kernel/signal.c
@@ -2714,7 +2714,16 @@
 extern void recalc_sigpending_and_wake(struct task_struct *t);
 extern void recalc_sigpending(void);
  
-extern void signal_wake_up(struct task_struct *t, int resume_stopped);
+extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
+
+static inline void signal_wake_up(struct task_struct *t, bool resume)
+{
+	signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
+}
+static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
+{
+	signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
+}
  
 /*
  * Wrappers for p->thread_info->cpu access. No-op on UP.
@@ -117,7 +117,7 @@
 	 * TASK_KILLABLE sleeps.
 	 */
 	if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
-		signal_wake_up(child, task_is_traced(child));
+		ptrace_signal_wake_up(child, true);
  
 	spin_unlock(&child->sighand->siglock);
 }
@@ -317,7 +317,7 @@
 	 */
 	if (task_is_stopped(task) &&
 	    task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
-		signal_wake_up(task, 1);
+		signal_wake_up_state(task, __TASK_STOPPED);
  
 	spin_unlock(&task->sighand->siglock);
  
@@ -737,7 +737,7 @@
 		 * tracee into STOP.
 		 */
 		if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
-			signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
+			ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
  
 		unlock_task_sighand(child, &flags);
 		ret = 0;
@@ -763,7 +763,7 @@
 			 * start of this trap and now.  Trigger re-trap.
 			 */
 			if (child->jobctl & JOBCTL_TRAP_NOTIFY)
-				signal_wake_up(child, true);
+				ptrace_signal_wake_up(child, true);
 			ret = 0;
 		}
 		unlock_task_sighand(child, &flags);
@@ -680,23 +680,17 @@
  * No need to set need_resched since signal event passing
  * goes through ->blocked
  */
-void signal_wake_up(struct task_struct *t, int resume)
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
 {
-	unsigned int mask;
-
 	set_tsk_thread_flag(t, TIF_SIGPENDING);
-
 	/*
-	 * For SIGKILL, we want to wake it up in the stopped/traced/killable
+	 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
 	 * case. We don't check t->state here because there is a race with it
 	 * executing another processor and just now entering stopped state.
 	 * By using wake_up_state, we ensure the process will wake up and
 	 * handle its death signal.
 	 */
-	mask = TASK_INTERRUPTIBLE;
-	if (resume)
-		mask |= TASK_WAKEKILL;
-	if (!wake_up_state(t, mask))
+	if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
 		kick_process(t);
 }
  
@@ -844,7 +838,7 @@
 	assert_spin_locked(&t->sighand->siglock);
  
 	task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
-	signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+	ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
 }
  
 /*
...	...	@@ -2714,7 +2714,16 @@
2714	2714	extern void recalc_sigpending_and_wake(struct task_struct *t);
2715	2715	extern void recalc_sigpending(void);
2716	2716
2717		-extern void signal_wake_up(struct task_struct *t, int resume_stopped);
	2717	+extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
	2718	+
	2719	+static inline void signal_wake_up(struct task_struct *t, bool resume)
	2720	+{
	2721	+ signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
	2722	+}
	2723	+static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
	2724	+{
	2725	+ signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
	2726	+}
2718	2727
2719	2728	/*
2720	2729	* Wrappers for p->thread_info->cpu access. No-op on UP.
...	...	@@ -117,7 +117,7 @@
117	117	* TASK_KILLABLE sleeps.
118	118	*/
119	119	if (child->jobctl & JOBCTL_STOP_PENDING \|\| task_is_traced(child))
120		- signal_wake_up(child, task_is_traced(child));
	120	+ ptrace_signal_wake_up(child, true);
121	121
122	122	spin_unlock(&child->sighand->siglock);
123	123	}
...	...	@@ -317,7 +317,7 @@
317	317	*/
318	318	if (task_is_stopped(task) &&
319	319	task_set_jobctl_pending(task, JOBCTL_TRAP_STOP \| JOBCTL_TRAPPING))
320		- signal_wake_up(task, 1);
	320	+ signal_wake_up_state(task, __TASK_STOPPED);
321	321
322	322	spin_unlock(&task->sighand->siglock);
323	323
...	...	@@ -737,7 +737,7 @@
737	737	* tracee into STOP.
738	738	*/
739	739	if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
740		- signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
	740	+ ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
741	741
742	742	unlock_task_sighand(child, &flags);
743	743	ret = 0;
...	...	@@ -763,7 +763,7 @@
763	763	* start of this trap and now. Trigger re-trap.
764	764	*/
765	765	if (child->jobctl & JOBCTL_TRAP_NOTIFY)
766		- signal_wake_up(child, true);
	766	+ ptrace_signal_wake_up(child, true);
767	767	ret = 0;
768	768	}
769	769	unlock_task_sighand(child, &flags);
...	...	@@ -680,23 +680,17 @@
680	680	* No need to set need_resched since signal event passing
681	681	* goes through ->blocked
682	682	*/
683		-void signal_wake_up(struct task_struct *t, int resume)
	683	+void signal_wake_up_state(struct task_struct *t, unsigned int state)
684	684	{
685		- unsigned int mask;
686		-
687	685	set_tsk_thread_flag(t, TIF_SIGPENDING);
688		-
689	686	/*
690		- * For SIGKILL, we want to wake it up in the stopped/traced/killable
	687	+ * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
691	688	* case. We don't check t->state here because there is a race with it
692	689	* executing another processor and just now entering stopped state.
693	690	* By using wake_up_state, we ensure the process will wake up and
694	691	* handle its death signal.
695	692	*/
696		- mask = TASK_INTERRUPTIBLE;
697		- if (resume)
698		- mask \|= TASK_WAKEKILL;
699		- if (!wake_up_state(t, mask))
	693	+ if (!wake_up_state(t, state \| TASK_INTERRUPTIBLE))
700	694	kick_process(t);
701	695	}
702	696
...	...	@@ -844,7 +838,7 @@
844	838	assert_spin_locked(&t->sighand->siglock);
845	839
846	840	task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
847		- signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
	841	+ ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
848	842	}
849	843
850	844	/*