Re: lockdep: possible reason: unannotated irqs-off. (was: Re:Linux 2.6.38-rc4)

[Yong Zhang]

On Tue, Feb 08, 2011 at 03:18:00PM +0100, Peter Zijlstra wrote:
> Subject: lockdep, timer: Revert the del_timer_sync() annotation
> 
> Both attempts at trying to allow softirq usage failed, revert for this
> release and try again later.
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> ---
>  kernel/timer.c |    8 +++-----
>  1 files changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/timer.c b/kernel/timer.c
> index 343ff27..c848cd8 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

I think we don't need to revert this comment.

>   * 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);

Going back to local_irq_save()/local_irq_restore() doesn't prevent
it from using in softirq context.

Thanks,
Yong
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