* [PATCH] wakeup: Use irqsave/irqrestore for events_lock
@ 2012-09-06 18:07 John Stultz
2012-09-06 21:35 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: John Stultz @ 2012-09-06 18:07 UTC (permalink / raw)
To: lkml
Cc: John Stultz, Rafael J. Wysocki, Android Team,
Arve Hjønnevåg, Jon Medhurst (Tixy)
Jon Medhurst (Tixy) recently noticed a problem with the
events_lock usage. One of the Android patches that uses
wakeup_sources calls wakeup_source_add() with irqs disabled.
However, the event_lock usage in wakeup_source_add() uses
spin_lock_irq()/spin_unlock_irq(), which reenables interrupts.
This results in lockdep warnings.
The fix is to use spin_lock_irqsave()/spin_lock_irqrestore()
instead for the events_lock.
Full bug report here:
https://bugs.launchpad.net/linaro-landing-team-arm/+bug/1037565
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Android Team <kernel-team@android.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
Reported-and-debugged-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/base/power/wakeup.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index cbb463b..0e4b093 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -127,6 +127,8 @@ EXPORT_SYMBOL_GPL(wakeup_source_destroy);
*/
void wakeup_source_add(struct wakeup_source *ws)
{
+ unsigned long flags;
+
if (WARN_ON(!ws))
return;
@@ -135,9 +137,9 @@ void wakeup_source_add(struct wakeup_source *ws)
ws->active = false;
ws->last_time = ktime_get();
- spin_lock_irq(&events_lock);
+ spin_lock_irqsave(&events_lock, flags);
list_add_rcu(&ws->entry, &wakeup_sources);
- spin_unlock_irq(&events_lock);
+ spin_unlock_irqrestore(&events_lock, flags);
}
EXPORT_SYMBOL_GPL(wakeup_source_add);
@@ -147,12 +149,14 @@ EXPORT_SYMBOL_GPL(wakeup_source_add);
*/
void wakeup_source_remove(struct wakeup_source *ws)
{
+ unsigned long flags;
+
if (WARN_ON(!ws))
return;
- spin_lock_irq(&events_lock);
+ spin_lock_irqsave(&events_lock, flags);
list_del_rcu(&ws->entry);
- spin_unlock_irq(&events_lock);
+ spin_unlock_irqrestore(&events_lock, flags);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(wakeup_source_remove);
@@ -723,15 +727,16 @@ bool pm_get_wakeup_count(unsigned int *count, bool block)
bool pm_save_wakeup_count(unsigned int count)
{
unsigned int cnt, inpr;
+ unsigned long flags;
events_check_enabled = false;
- spin_lock_irq(&events_lock);
+ spin_lock_irqsave(&events_lock, flags);
split_counters(&cnt, &inpr);
if (cnt == count && inpr == 0) {
saved_count = count;
events_check_enabled = true;
}
- spin_unlock_irq(&events_lock);
+ spin_unlock_irqrestore(&events_lock, flags);
return events_check_enabled;
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] wakeup: Use irqsave/irqrestore for events_lock
2012-09-06 18:07 [PATCH] wakeup: Use irqsave/irqrestore for events_lock John Stultz
@ 2012-09-06 21:35 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2012-09-06 21:35 UTC (permalink / raw)
To: John Stultz
Cc: lkml, Android Team, Arve Hjønnevåg, Jon Medhurst (Tixy)
On Thursday, September 06, 2012, John Stultz wrote:
> Jon Medhurst (Tixy) recently noticed a problem with the
> events_lock usage. One of the Android patches that uses
> wakeup_sources calls wakeup_source_add() with irqs disabled.
> However, the event_lock usage in wakeup_source_add() uses
> spin_lock_irq()/spin_unlock_irq(), which reenables interrupts.
> This results in lockdep warnings.
>
> The fix is to use spin_lock_irqsave()/spin_lock_irqrestore()
> instead for the events_lock.
>
> Full bug report here:
> https://bugs.launchpad.net/linaro-landing-team-arm/+bug/1037565
>
> Cc: Rafael J. Wysocki <rjw@sisk.pl>
> Cc: Android Team <kernel-team@android.com>
> Cc: Arve Hjønnevåg <arve@android.com>
> Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
> Reported-and-debugged-by: Jon Medhurst (Tixy) <tixy@linaro.org>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
Thanks, applied to the linux-next brach of the linux-pm.git tree as v3.7
material.
Please consider CCing PM-related patches to linux-pm@vger.kernel.org in the
future, that makes it much easier for me to handle them.
Thanks,
Rafael
> ---
> drivers/base/power/wakeup.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index cbb463b..0e4b093 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -127,6 +127,8 @@ EXPORT_SYMBOL_GPL(wakeup_source_destroy);
> */
> void wakeup_source_add(struct wakeup_source *ws)
> {
> + unsigned long flags;
> +
> if (WARN_ON(!ws))
> return;
>
> @@ -135,9 +137,9 @@ void wakeup_source_add(struct wakeup_source *ws)
> ws->active = false;
> ws->last_time = ktime_get();
>
> - spin_lock_irq(&events_lock);
> + spin_lock_irqsave(&events_lock, flags);
> list_add_rcu(&ws->entry, &wakeup_sources);
> - spin_unlock_irq(&events_lock);
> + spin_unlock_irqrestore(&events_lock, flags);
> }
> EXPORT_SYMBOL_GPL(wakeup_source_add);
>
> @@ -147,12 +149,14 @@ EXPORT_SYMBOL_GPL(wakeup_source_add);
> */
> void wakeup_source_remove(struct wakeup_source *ws)
> {
> + unsigned long flags;
> +
> if (WARN_ON(!ws))
> return;
>
> - spin_lock_irq(&events_lock);
> + spin_lock_irqsave(&events_lock, flags);
> list_del_rcu(&ws->entry);
> - spin_unlock_irq(&events_lock);
> + spin_unlock_irqrestore(&events_lock, flags);
> synchronize_rcu();
> }
> EXPORT_SYMBOL_GPL(wakeup_source_remove);
> @@ -723,15 +727,16 @@ bool pm_get_wakeup_count(unsigned int *count, bool block)
> bool pm_save_wakeup_count(unsigned int count)
> {
> unsigned int cnt, inpr;
> + unsigned long flags;
>
> events_check_enabled = false;
> - spin_lock_irq(&events_lock);
> + spin_lock_irqsave(&events_lock, flags);
> split_counters(&cnt, &inpr);
> if (cnt == count && inpr == 0) {
> saved_count = count;
> events_check_enabled = true;
> }
> - spin_unlock_irq(&events_lock);
> + spin_unlock_irqrestore(&events_lock, flags);
> return events_check_enabled;
> }
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2012-09-06 21:29 UTC | newest]
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2012-09-06 21:35 ` Rafael J. Wysocki
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