This is a note to let you know that I've just added the patch titled
alarmtimer: Lock k_itimer during timer callback
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alarmtimer-lock-k_itimer-during-timer-callback.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 474e941bed9262f5fa2394f9a4a67e24499e5926 Mon Sep 17 00:00:00 2001
From: Richard Larocque <rlarocque@xxxxxxxxxx>
Date: Tue, 9 Sep 2014 18:31:05 -0700
Subject: alarmtimer: Lock k_itimer during timer callback
From: Richard Larocque <rlarocque@xxxxxxxxxx>
commit 474e941bed9262f5fa2394f9a4a67e24499e5926 upstream.
Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.
The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn(). The alarm timers follow a different path, so they
ought to grab the lock somewhere else.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Sharvil Nanavati <sharvil@xxxxxxxxxx>
Signed-off-by: Richard Larocque <rlarocque@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/time/alarmtimer.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -464,8 +464,12 @@ static enum alarmtimer_type clock2alarm(
static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
ktime_t now)
{
+ unsigned long flags;
struct k_itimer *ptr = container_of(alarm, struct k_itimer,
it.alarm.alarmtimer);
+ enum alarmtimer_restart result = ALARMTIMER_NORESTART;
+
+ spin_lock_irqsave(&ptr->it_lock, flags);
if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
if (posix_timer_event(ptr, 0) != 0)
ptr->it_overrun++;
@@ -475,9 +479,11 @@ static enum alarmtimer_restart alarm_han
if (ptr->it.alarm.interval.tv64) {
ptr->it_overrun += alarm_forward(alarm, now,
ptr->it.alarm.interval);
- return ALARMTIMER_RESTART;
+ result = ALARMTIMER_RESTART;
}
- return ALARMTIMER_NORESTART;
+ spin_unlock_irqrestore(&ptr->it_lock, flags);
+
+ return result;
}
/**
Patches currently in stable-queue which might be from rlarocque@xxxxxxxxxx are
queue-3.14/alarmtimer-return-relative-times-in-timer_gettime.patch
queue-3.14/alarmtimer-do-not-signal-sigev_none-timers.patch
queue-3.14/alarmtimer-lock-k_itimer-during-timer-callback.patch
--
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