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Hi Fengguang,
Thanks for your test and reporting.
On Sun, Jan 12, 2014 at 12:14 AM, kernel test robot
<[email protected]> wrote:
> Greetings,
>
> I got the below dmesg and the first bad commit is
>
> commit 97e890b9c839c191a500c3a19bfb4539f65c70be
> Author: Ming Lei <[email protected]>
> AuthorDate: Fri Jan 10 12:41:46 2014 +1100
> Commit: Stephen Rothwell <[email protected]>
> CommitDate: Fri Jan 10 12:41:46 2014 +1100
>
> lib/percpu_counter.c: disable local irq when updating percpu couter
>
> __percpu_counter_add() may be called in softirq/hardirq handler (such as,
> blk_mq_queue_exit() is typically called in hardirq/softirq handler), so we
> need to disable local irq when updating the percpu counter, otherwise
> counts may be lost.
>
> The patch fixes problem that 'rmmod null_blk' may hang in blk_cleanup_queue()
> because of miscounting of request_queue->mq_usage_counter.
>
> Signed-off-by: Ming Lei <[email protected]>
> Cc: Paul Gortmaker <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Shaohua Li <[email protected]>
> Cc: Jens Axboe <[email protected]>
> Cc: Fan Du <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
>
> +-----------------------------------------------------------+----+
> | | |
> +-----------------------------------------------------------+----+
> | boot_successes | 0 |
> | boot_failures | 19 |
> | WARNING:CPU:PID:at_kernel/locking/lockdep.c:check_flags() | 19 |
> +-----------------------------------------------------------+----+
>
> [ 8.021637] Freeing unused kernel memory: 816K (ffff880001934000 - ffff880001a00000)
>
> [ 8.093354] ------------[ cut here ]------------
> [ 8.095469] WARNING: CPU: 1 PID: 1 at kernel/locking/lockdep.c:3537 check_flags+0x77/0x1ba()
> [ 8.095469] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
The warning is caused by the added raw_local_irq_save(), which should
have been local_irq_save(flags). Actually, it is a false positive.
Andrew, considered that your approach may be more efficient than this
one since preempt_disable()/preempt_enable() can be removed too.
So could you prepare one patch for fixing the problem? Or if you are busy, I'd
like to do it.
Thanks,
--
Ming Lei
On Sun, 12 Jan 2014 00:36:07 +0800 Ming Lei <[email protected]> wrote:
> >
> > [ 8.093354] ------------[ cut here ]------------
> > [ 8.095469] WARNING: CPU: 1 PID: 1 at kernel/locking/lockdep.c:3537 check_flags+0x77/0x1ba()
> > [ 8.095469] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
>
> The warning is caused by the added raw_local_irq_save(), which should
> have been local_irq_save(flags). Actually, it is a false positive.
>
> Andrew, considered that your approach may be more efficient than this
> one since preempt_disable()/preempt_enable() can be removed too.
>
> So could you prepare one patch for fixing the problem? Or if you are busy, I'd
> like to do it.
Yes, please send a fresh patch.