From: Oleg Nesterov <oleg@tv-sign.ru>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Austin Clements <amdragon+kernelbugzilla@mit.edu>,
Ingo Molnar <mingo@elte.hu>, john stultz <johnstul@us.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michael Kerrisk <mtk.manpages@googlemail.com>,
Roland McGrath <roland@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: [PATCH 4/4] posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process);
Date: Sat, 3 May 2008 21:35:54 +0400 [thread overview]
Message-ID: <20080503173554.GA8112@tv-sign.ru> (raw)
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 <oleg@tv-sign.ru>
--- 25/kernel/posix-timers.c~4_RPT_NO_CHECK 2008-05-03 19:55:27.000000000 +0400
+++ 25/kernel/posix-timers.c 2008-05-03 20:13:36.000000000 +0400
@@ -450,9 +450,6 @@ static void release_posix_timer(struct k
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);
}
next reply other threads:[~2008-05-03 17:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-03 17:35 Oleg Nesterov [this message]
2008-05-06 2:34 ` Roland McGrath
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