Messages in this thread Patch in this message | | | From | (Eric W. Biederman) | Date | Fri, 28 Feb 2020 11:15:03 -0600 | Subject | [PATCH 5/5] posix-cpu-timers: Stop disabling timers on mt-exec |
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The reasons Oleg added the extra posix_cpu_timers_exit_group are not entirely clear from his commit message. Today all that posix_cpu_timers_exit_group does is stop timers that are tracking the task from firing. Every other operation on those timers is still allowed.
The practical implication of this is posix_cpu_timer_del which could not get the siglock after the thread group leader has exited (because sighand == NULL) would be able to run successfully because the timer was already dequeued.
With that locking issue fixed there is no point in disabling all of the timers. So remove Oleg's ``tempoary'' hack.
Fixes: e0a70217107e ("posix-cpu-timers: workaround to suppress the problems with mt exec") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> --- kernel/exit.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/kernel/exit.c b/kernel/exit.c index 502b4995b688..c7f32101c2c8 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -103,17 +103,8 @@ static void __exit_signal(struct task_struct *tsk) #ifdef CONFIG_POSIX_TIMERS posix_cpu_timers_exit(tsk); - if (group_dead) { + if (group_dead) posix_cpu_timers_exit_group(tsk); - } 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); - } #endif if (group_dead) { -- 2.25.0
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