linux-kernel - [tip:timers/urgent] posix_cpu_timer: Exit early when process has been reaped

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Message-ID: <tip-2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307@git.kernel.org>
Date:	Mon, 11 Jul 2016 08:25:49 -0700
From:	tip-bot for Alexey Dobriyan <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	tglx@...utronix.de, mingo@...nel.org, linux-kernel@...r.kernel.org,
	hpa@...or.com, adobriyan@...il.com
Subject: [tip:timers/urgent] posix_cpu_timer: Exit early when process has
 been reaped

Commit-ID:  2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307
Gitweb:     http://git.kernel.org/tip/2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307
Author:     Alexey Dobriyan <adobriyan@...il.com>
AuthorDate: Fri, 8 Jul 2016 01:39:11 +0300
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 11 Jul 2016 17:20:12 +0200

posix_cpu_timer: Exit early when process has been reaped

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@...il.com>
Cc: stable@...r.kernel.org
Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 kernel/time/posix-cpu-timers.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 1cafba8..39008d7 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -777,6 +777,7 @@ 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);