From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Thu, 7 Jul 2016 22:39:11 +0000 (+0300)
Subject: posix_cpu_timer: Exit early when process has been reaped
X-Git-Tag: v3.16.39~290
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b829502b93d7dc1d6c2bd220b1d3137155517d10;p=thirdparty%2Fkernel%2Fstable.git

posix_cpu_timer: Exit early when process has been reaped

commit 2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307 upstream.

Variable "now" seems to be genuinely used unintialized
if branch

	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {

is not taken and branch

	if (unlikely(sighand == NULL)) {

is taken. In this case the process has been reaped and the timer is marked as
disarmed anyway. So none of the postprocessing of the sample is
required. Return right away.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 3b8946416a5f8..4bd1dd7db1a12 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -798,6 +798,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 			timer->it.cpu.expires = 0;
 			sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
 					   &itp->it_value);
+			return;
 		} else {
 			cpu_timer_sample_group(timer->it_clock, p, &now);
 			unlock_task_sighand(p, &flags);