Commit 45cdf5cc0703c537194588c63d53bad1f2539d36
1 parent
53c8f9f199
Exists in
master
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6 other branches
kill tracehook_notify_death()
Kill tracehook_notify_death(), reimplement the logic in its caller,
exit_notify().
Also, change the exec_id's check to use thread_group_leader() instead
of task_detached(), this is more clear. This logic only applies to
the exiting leader, a sub-thread must never change its exit_signal.
Note: when the traced group leader exits the exit_signal-or-SIGCHLD
logic looks really strange:
- we notify the tracer even if !thread_group_empty() but
do_wait(WEXITED) can't work until all threads exit
- if the tracer is real_parent, it is not clear why can't
we use ->exit_signal event if !thread_group_empty()
-v2: do not try to fix the 2nd oddity to avoid the subtle behavior
change mixed with reorganization, suggested by Tejun.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Showing 2 changed files with 13 additions and 42 deletions Side-by-side Diff
include/linux/tracehook.h
| ... | ... | @@ -152,40 +152,6 @@ |
| 152 | 152 | ptrace_notify(SIGTRAP); |
| 153 | 153 | } |
| 154 | 154 | |
| 155 | -#define DEATH_REAP -1 | |
| 156 | -#define DEATH_DELAYED_GROUP_LEADER -2 | |
| 157 | - | |
| 158 | -/** | |
| 159 | - * tracehook_notify_death - task is dead, ready to notify parent | |
| 160 | - * @task: @current task now exiting | |
| 161 | - * @death_cookie: value to pass to tracehook_report_death() | |
| 162 | - * @group_dead: nonzero if this was the last thread in the group to die | |
| 163 | - * | |
| 164 | - * A return value >= 0 means call do_notify_parent() with that signal | |
| 165 | - * number. Negative return value can be %DEATH_REAP to self-reap right | |
| 166 | - * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our | |
| 167 | - * parent. Note that a return value of 0 means a do_notify_parent() call | |
| 168 | - * that sends no signal, but still wakes up a parent blocked in wait*(). | |
| 169 | - * | |
| 170 | - * Called with write_lock_irq(&tasklist_lock) held. | |
| 171 | - */ | |
| 172 | -static inline int tracehook_notify_death(struct task_struct *task, | |
| 173 | - void **death_cookie, int group_dead) | |
| 174 | -{ | |
| 175 | - if (task_detached(task)) | |
| 176 | - return task->ptrace ? SIGCHLD : DEATH_REAP; | |
| 177 | - | |
| 178 | - /* | |
| 179 | - * If something other than our normal parent is ptracing us, then | |
| 180 | - * send it a SIGCHLD instead of honoring exit_signal. exit_signal | |
| 181 | - * only has special meaning to our real parent. | |
| 182 | - */ | |
| 183 | - if (thread_group_empty(task) && !ptrace_reparented(task)) | |
| 184 | - return task->exit_signal; | |
| 185 | - | |
| 186 | - return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; | |
| 187 | -} | |
| 188 | - | |
| 189 | 155 | #ifdef TIF_NOTIFY_RESUME |
| 190 | 156 | /** |
| 191 | 157 | * set_notify_resume - cause tracehook_notify_resume() to be called |
kernel/exit.c
| ... | ... | @@ -819,9 +819,7 @@ |
| 819 | 819 | */ |
| 820 | 820 | static void exit_notify(struct task_struct *tsk, int group_dead) |
| 821 | 821 | { |
| 822 | - int signal; | |
| 823 | 822 | bool autoreap; |
| 824 | - void *cookie; | |
| 825 | 823 | |
| 826 | 824 | /* |
| 827 | 825 | * This does two things: |
| 828 | 826 | |
| ... | ... | @@ -852,16 +850,23 @@ |
| 852 | 850 | * we have changed execution domain as these two values started |
| 853 | 851 | * the same after a fork. |
| 854 | 852 | */ |
| 855 | - if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) && | |
| 853 | + if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD && | |
| 856 | 854 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id || |
| 857 | 855 | tsk->self_exec_id != tsk->parent_exec_id)) |
| 858 | 856 | tsk->exit_signal = SIGCHLD; |
| 859 | 857 | |
| 860 | - signal = tracehook_notify_death(tsk, &cookie, group_dead); | |
| 861 | - if (signal >= 0) | |
| 862 | - autoreap = do_notify_parent(tsk, signal); | |
| 863 | - else | |
| 864 | - autoreap = (signal == DEATH_REAP); | |
| 858 | + if (unlikely(tsk->ptrace)) { | |
| 859 | + int sig = thread_group_leader(tsk) && | |
| 860 | + thread_group_empty(tsk) && | |
| 861 | + !ptrace_reparented(tsk) ? | |
| 862 | + tsk->exit_signal : SIGCHLD; | |
| 863 | + autoreap = do_notify_parent(tsk, sig); | |
| 864 | + } else if (thread_group_leader(tsk)) { | |
| 865 | + autoreap = thread_group_empty(tsk) && | |
| 866 | + do_notify_parent(tsk, tsk->exit_signal); | |
| 867 | + } else { | |
| 868 | + autoreap = true; | |
| 869 | + } | |
| 865 | 870 | |
| 866 | 871 | tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE; |
| 867 | 872 |