From f266a5110d453b7987194460ac7edd31f1a5426c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 3 Feb 2011 15:09:41 +0100 Subject: lockdep, timer: Fix del_timer_sync() annotation Calling local_bh_enable() will want to actually start processing softirqs, which isn't a good idea since this can get called with IRQs disabled. Cure this by using _local_bh_enable() which doesn't start processing softirqs, and use raw_local_irq_save() to avoid any softirqs from happening without letting lockdep think IRQs are in fact disabled. Reported-by: Nick Bowler Signed-off-by: Peter Zijlstra Reviewed-by: Yong Zhang LKML-Reference: <20110203141548.039540914@chello.nl> Signed-off-by: Thomas Gleixner --- kernel/timer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index 43ca9936f2d0..d53ce66daea0 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -969,10 +969,14 @@ EXPORT_SYMBOL(try_to_del_timer_sync); int del_timer_sync(struct timer_list *timer) { #ifdef CONFIG_LOCKDEP + unsigned long flags; + + raw_local_irq_save(flags); local_bh_disable(); lock_map_acquire(&timer->lockdep_map); lock_map_release(&timer->lockdep_map); - local_bh_enable(); + _local_bh_enable(); + raw_local_irq_restore(flags); #endif /* * don't use it in hardirq context, because it -- cgit v1.2.3 From 7ff207928eb0761fa6b6c39eda82ac07a5241acf Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 8 Feb 2011 15:18:00 +0100 Subject: Revert "lockdep, timer: Fix del_timer_sync() annotation" Both attempts at trying to allow softirq usage for del_timer_sync() failed (produced bogus warnings), so revert the commit for this release: f266a5110d45: lockdep, timer: Fix del_timer_sync() annotation and try again later. Reported-by: Borislav Petkov Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Yong Zhang Cc: Thomas Gleixner LKML-Reference: <1297174680.13327.107.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/timer.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index d53ce66daea0..d6459923d245 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -959,7 +959,7 @@ EXPORT_SYMBOL(try_to_del_timer_sync); * * Synchronization rules: Callers must prevent restarting of the timer, * otherwise this function is meaningless. It must not be called from - * hardirq contexts. The caller must not hold locks which would prevent + * interrupt contexts. The caller must not hold locks which would prevent * completion of the timer's handler. The timer's handler must not call * add_timer_on(). Upon exit the timer is not queued and the handler is * not running on any CPU. @@ -971,12 +971,10 @@ int del_timer_sync(struct timer_list *timer) #ifdef CONFIG_LOCKDEP unsigned long flags; - raw_local_irq_save(flags); - local_bh_disable(); + local_irq_save(flags); lock_map_acquire(&timer->lockdep_map); lock_map_release(&timer->lockdep_map); - _local_bh_enable(); - raw_local_irq_restore(flags); + local_irq_restore(flags); #endif /* * don't use it in hardirq context, because it -- cgit v1.2.3