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 <[email protected]> > Cc: Android Team <[email protected]> > Cc: Arve Hjønnevåg <[email protected]> > Cc: Jon Medhurst (Tixy) <[email protected]> > Reported-and-debugged-by: Jon Medhurst (Tixy) <[email protected]> > Signed-off-by: John Stultz <[email protected]>
Thanks, applied to the linux-next brach of the linux-pm.git tree as v3.7 material. Please consider CCing PM-related patches to [email protected] 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; > } > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
