The patch titled
posix-timers: don't switch to ->group_leader if ->it_process dies
has been removed from the -mm tree. Its filename was
posix-timers-dont-switch-to-group_leader-if-it_process-dies.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: posix-timers: don't switch to ->group_leader if ->it_process dies
From: Oleg Nesterov <oleg@xxxxxxxxxx>
posix_timer_event() drops SIGEV_THREAD_ID and switches to ->group_leader
if send_sigqueue() fails.
This is not very useful and doesn't work reliably. send_sigqueue() can
only fail if ->it_process is dead. But it can die before it dequeues the
SI_TIMER signal, in that case the timer stops anyway.
Remove this code. I guess it was needed a long ago to ensure that the
timer is not destroyed when when its creator thread dies.
Q: perhaps it makes sense to change sys_timer_settime() to return an error
if ->it_process is dead?
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/posix-timers.c | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
diff -puN kernel/posix-timers.c~posix-timers-dont-switch-to-group_leader-if-it_process-dies kernel/posix-timers.c
--- a/kernel/posix-timers.c~posix-timers-dont-switch-to-group_leader-if-it_process-dies
+++ a/kernel/posix-timers.c
@@ -313,6 +313,7 @@ void do_schedule_next_timer(struct sigin
int posix_timer_event(struct k_itimer *timr, int si_private)
{
+ int shared, ret;
/*
* FIXME: if ->sigq is queued we can race with
* dequeue_signal()->do_schedule_next_timer().
@@ -331,20 +332,10 @@ int posix_timer_event(struct k_itimer *t
timr->sigq->info.si_tid = timr->it_id;
timr->sigq->info.si_value = timr->it_sigev_value;
- if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
- struct task_struct *leader;
- int ret = send_sigqueue(timr->sigq, timr->it_process, 0);
-
- if (likely(ret >= 0))
- return ret;
-
- timr->it_sigev_notify = SIGEV_SIGNAL;
- leader = timr->it_process->group_leader;
- put_task_struct(timr->it_process);
- timr->it_process = leader;
- }
-
- return send_sigqueue(timr->sigq, timr->it_process, 1);
+ shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
+ ret = send_sigqueue(timr->sigq, timr->it_process, shared);
+ /* If we failed to send the signal the timer stops. */
+ return ret > 0;
}
EXPORT_SYMBOL_GPL(posix_timer_event);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
git-tip.patch
posix-timers-use-struct-pid-instead-of-struct-task_struct.patch
posix-timers-check-it_signal-instead-of-it_pid-to-validate-the-timer.patch
posix-timers-simplify-de_thread-exit_itimers-path.patch
signal-procfs-lock_task_sighand-do-not-need-rcu_read_lock.patch
make-ptrace_untrace-static.patch
coredump-format_corename-dont-append-%pid-if-multi-threaded.patch
add-config_core_dump_default_elf_headers.patch
kthread_bind-use-wait_task_inactivetask_uninterruptible.patch
pid_ns-de_thread-kill-the-now-unneeded-child_reaper-change.patch
pid_ns-kill-the-now-unused-task_child_reaper.patch
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