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authorStanislaw Gruszka <sgruszka@redhat.com>2013-02-15 11:08:11 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-28 06:58:59 -0800
commit7c3e516d99265e4aa915f3c05611b0f426bf8ce3 (patch)
treeca0e3900b725d528910363170a55f591c40fec50 /kernel
parentb3c57f009cfd9ed81737169c4026bfd03191d993 (diff)
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> Link: http://lkml.kernel.org/r/20130215100810.GF4392@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/posix-cpu-timers.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 125cb67daa21..acbb79c9092c 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1422,8 +1422,10 @@ 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;
}
@@ -1441,9 +1443,26 @@ 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.