From: Oleg Nesterov Date: Fri, 25 Jul 2008 08:47:27 +0000 (-0700) Subject: posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process); X-Git-Tag: v2.6.27-rc1~361 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=96347e7759e2e433c427defa0fa1adfc8cce6226;p=linux-2.6 posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process); release_posix_timer() can't be called with ->it_process != NULL. Once sys_timer_create() sets ->it_process it must not call release_posix_timer(), otherwise we can race with another thread doing sys_timer_delete(), this timer is visible to idr_find() and unlocked. The same is true for two other callers (actually, for any possible caller), sys_timer_delete() and itimer_delete(). They must clear ->it_process before unlock_timer() + release_posix_timer(). Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Cc: john stultz Cc: Thomas Gleixner Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 17f53266fb..9a21681aa8 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -449,9 +449,6 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set) spin_unlock_irqrestore(&idr_lock, flags); } sigqueue_free(tmr->sigq); - if (unlikely(tmr->it_process) && - tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) - put_task_struct(tmr->it_process); kmem_cache_free(posix_timers_cache, tmr); }