linux-kernel - [tip:timers/core] posix-timers: Zero out oldval itimerspec

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Date:   Mon, 12 Jun 2017 12:13:15 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, linux-kernel@...r.kernel.org, gorcunov@...nvz.org,
        john.stultz@...aro.org, mingo@...nel.org, tglx@...utronix.de,
        avagin@...tuozzo.com, peterz@...radead.org
Subject: [tip:timers/core] posix-timers: Zero out oldval itimerspec

Commit-ID:  5c7a3a3d20a4e175304c0e23809e3d70be8fed8a
Gitweb:     http://git.kernel.org/tip/5c7a3a3d20a4e175304c0e23809e3d70be8fed8a
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 12 Jun 2017 19:44:09 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 12 Jun 2017 21:07:40 +0200

posix-timers: Zero out oldval itimerspec

The recent posix timer rework moved the clearing of the itimerspec to the
real syscall implementation, but forgot that the kclock->timer_get() is
used by timer_settime() as well. That results in an uninitialized variable
and bogus values returned to user space.

Add the missing memset to timer_settime().

Fixes: eabdec043853 ("posix-timers: Zero settings value in common code")
Reported-by: Andrei Vagin <avagin@...tuozzo.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: John Stultz <john.stultz@...aro.org>
Cc: Cyrill Gorcunov <gorcunov@...nvz.org>
Link: http://lkml.kernel.org/r/20170609201156.GB21491@outlook.office365.com
---
 kernel/time/posix-timers.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index b53a0b5..88517dc 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -828,6 +828,8 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
 	if (!timespec64_valid(&new_spec64.it_interval) ||
 	    !timespec64_valid(&new_spec64.it_value))
 		return -EINVAL;
+	if (rtn)
+		memset(rtn, 0, sizeof(*rtn));
 retry:
 	timr = lock_timer(timer_id, &flag);
 	if (!timr)