Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932564AbaBEUzA (ORCPT ); Wed, 5 Feb 2014 15:55:00 -0500 Received: from mail.windriver.com ([147.11.1.11]:54882 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754647AbaBEUFr (ORCPT ); Wed, 5 Feb 2014 15:05:47 -0500 From: Paul Gortmaker To: , CC: Stanislaw Gruszka , Dave Jones , John Stultz , Oleg Nesterov , Thomas Gleixner , Paul Gortmaker Subject: [v2.6.34-stable 081/213] posix-cpu-timers: Fix nanosleep task_struct leak Date: Wed, 5 Feb 2014 15:00:36 -0500 Message-ID: <1391630568-49251-82-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> References: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stanislaw Gruszka ------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. ------------------- commit e6c42c295e071dd74a66b5a9fcf4f44049888ed8 upstream. The trinity fuzzer triggered a task_struct reference leak via clock_nanosleep with CPU_TIMERs. do_cpu_nanosleep() calls posic_cpu_timer_create(), but misses a corresponding posix_cpu_timer_del() which leads to the task_struct reference leak. Reported-and-tested-by: Tommi Rantala Signed-off-by: Stanislaw Gruszka Cc: Dave Jones Cc: John Stultz Cc: Oleg Nesterov Link: http://lkml.kernel.org/r/20130215100810.GF4392@redhat.com Signed-off-by: Thomas Gleixner Signed-off-by: Paul Gortmaker --- kernel/posix-cpu-timers.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index bc7704b3a443..3d83a1553a41 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1544,8 +1544,10 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags, while (!signal_pending(current)) { if (timer.it.cpu.expires.sched == 0) { /* - * Our timer fired and was reset. + * Our timer fired and was reset, below + * deletion can not fail. */ + posix_cpu_timer_del(&timer); spin_unlock_irq(&timer.it_lock); return 0; } @@ -1563,9 +1565,26 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags, * We were interrupted by a signal. */ sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp); - posix_cpu_timer_set(&timer, 0, &zero_it, it); + error = posix_cpu_timer_set(&timer, 0, &zero_it, it); + if (!error) { + /* + * Timer is now unarmed, deletion can not fail. + */ + posix_cpu_timer_del(&timer); + } spin_unlock_irq(&timer.it_lock); + while (error == TIMER_RETRY) { + /* + * We need to handle case when timer was or is in the + * middle of firing. In other cases we already freed + * resources. + */ + spin_lock_irq(&timer.it_lock); + error = posix_cpu_timer_del(&timer); + spin_unlock_irq(&timer.it_lock); + } + if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) { /* * It actually did fire already. -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/