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| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-07 15:38:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-07 16:36:05 -0700 |
| commit | b436069059fede30ca31d4bf439cc86436ff5b1d (patch) | |
| tree | d5d6875cdd317445cb1e84883b5a078bf8cf1451 | |
| parent | abd50b39e783e1b6c75c7534c37f1eb2d94a89cd (diff) | |
| download | linux-stable-b436069059fede30ca31d4bf439cc86436ff5b1d.tar.gz linux-stable-b436069059fede30ca31d4bf439cc86436ff5b1d.tar.bz2 linux-stable-b436069059fede30ca31d4bf439cc86436ff5b1d.zip | |
wait: use EXIT_TRACE only if thread_group_leader(zombie)
wait_task_zombie() always uses EXIT_TRACE/ptrace_unlink() if
ptrace_reparented(). This is suboptimal and a bit confusing: we do not
need do_notify_parent(p) if !thread_group_leader(p) and in this case we
also do not need ptrace_unlink(), we can rely on ptrace_release_task().
Change wait_task_zombie() to check thread_group_leader() along with
ptrace_reparented() and simplify the final p->exit_state transition.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Michal Schmidt <mschmidt@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Lennart Poettering <lpoetter@redhat.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/exit.c | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 022a0ff17318..4773ed990907 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1040,7 +1040,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) /* * Move the task's state to DEAD/TRACE, only one thread can do this. */ - state = traced ? EXIT_TRACE : EXIT_DEAD; + state = traced && thread_group_leader(p) ? EXIT_TRACE : EXIT_DEAD; if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE) return 0; /* @@ -1140,18 +1140,15 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) if (!retval) retval = pid; - if (traced) { + if (state == EXIT_TRACE) { 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. - */ - state = EXIT_DEAD; - if (thread_group_leader(p) && - !do_notify_parent(p, p->exit_signal)) - state = EXIT_ZOMBIE; + + /* If parent wants a zombie, don't release it now */ + state = EXIT_ZOMBIE; + if (do_notify_parent(p, p->exit_signal)) + state = EXIT_DEAD; p->exit_state = state; write_unlock_irq(&tasklist_lock); } |