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alarmtimer: Lock k_itimer during timer callback 

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: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Richard Larocque 2014-09-09 18:31:05 -07:00 committed by John Stultz
parent 265b81d23a
commit 474e941bed
1 changed files with 8 additions and 2 deletions
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10
kernel/time/alarmtimer.c
View File

@ -464,8 +464,12 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm, static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
ktime_t now) ktime_t now)
{ {
unsigned long flags;
struct k_itimer *ptr = container_of(alarm, struct k_itimer, struct k_itimer *ptr = container_of(alarm, struct k_itimer,
it.alarm.alarmtimer); 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 ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
if (posix_timer_event(ptr, 0) != 0) if (posix_timer_event(ptr, 0) != 0)
ptr->it_overrun++; ptr->it_overrun++;
@ -475,9 +479,11 @@ static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
if (ptr->it.alarm.interval.tv64) { if (ptr->it.alarm.interval.tv64) {
ptr->it_overrun += alarm_forward(alarm, now, ptr->it_overrun += alarm_forward(alarm, now,
ptr->it.alarm.interval); ptr->it.alarm.interval);
return ALARMTIMER_RESTART; result = ALARMTIMER_RESTART;
} }
return ALARMTIMER_NORESTART; spin_unlock_irqrestore(&ptr->it_lock, flags);
return result;
} }
/** /**