| From 3e7b85229b2303b3608b239931febc9b080925ff Mon Sep 17 00:00:00 2001 |
| From: Stanislaw Gruszka <sgruszka@redhat.com> |
| Date: Fri, 15 Feb 2013 11:08:11 +0100 |
| Subject: [PATCH] posix-cpu-timers: Fix nanosleep task_struct leak |
| |
| 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 <tt.rantala@gmail.com> |
| Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> |
| Cc: Dave Jones <davej@redhat.com> |
| Cc: John Stultz <john.stultz@linaro.org> |
| Cc: Oleg Nesterov <oleg@redhat.com> |
| Cc: stable@vger.kernel.org |
| Link: http://lkml.kernel.org/r/20130215100810.GF4392@redhat.com |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| 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 |
| |