Re: [PATCH] block: Fix possible sleep in invalid context

[Aaron Lu <aaron.lu@intel.com>]

On 07/01/2013 11:28 PM, Sujit Reddy Thumma wrote:
> When block runtime PM is enabled following warning is seen
> while resuming the device.
> 
> BUG: sleeping function called from invalid context at
> .../drivers/base/power/runtime.c:923
> in_atomic(): 1, irqs_disabled(): 128, pid: 12, name: kworker/0:1
> [<c0014448>] (unwind_backtrace+0x0/0x120) from
> [<c03120e4>] (__pm_runtime_suspend+0x34/0xa0) from
> [<c021c33c>] (blk_post_runtime_resume+0x4c/0x5c) from
> [<c03297cc>] (scsi_runtime_resume+0x90/0xb4) from
> [<c0310940>] (__rpm_callback+0x30/0x58) from
> [<c0310980>] (rpm_callback+0x18/0x28) from
> [<c0311ab0>] (rpm_resume+0x3dc/0x540) from
> [<c03120a4>] (pm_runtime_work+0x8c/0x98) from
> [<c007767c>] (process_one_work+0x238/0x3e4) from
> [<c0077b90>] (worker_thread+0x1ac/0x2ac) from
> [<c007cfdc>] (kthread+0x88/0x94) from
> [<c000ece0>] (kernel_thread_exit+0x0/0x8)
> 
> Fix this by releasing spin_lock_irq() before calling
> pm_runtime_autosuspend() in blk_post_runtime_resume().

Hi Sujit,

Thanks for testing out block layer runtime PM!

As for the problem here, it is already fixed by:

commit c60855cdb976c632b3bf8922eeab8a0e78edfc04
Author: Aaron Lu <aaron.lu@intel.com>
Date:   Fri May 17 15:47:20 2013 +0800

    blkpm: avoid sleep when holding queue lock

-Aaron

> 
> Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
> Cc: stable@vger.kernel.org
> ---
>  block/blk-core.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 33c33bc..2456116 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -3159,16 +3159,18 @@ EXPORT_SYMBOL(blk_pre_runtime_resume);
>   */
>  void blk_post_runtime_resume(struct request_queue *q, int err)
>  {
> -	spin_lock_irq(q->queue_lock);
>  	if (!err) {
> +		spin_lock_irq(q->queue_lock);
>  		q->rpm_status = RPM_ACTIVE;
>  		__blk_run_queue(q);
>  		pm_runtime_mark_last_busy(q->dev);
> +		spin_unlock_irq(q->queue_lock);
>  		pm_runtime_autosuspend(q->dev);
>  	} else {
> +		spin_lock_irq(q->queue_lock);
>  		q->rpm_status = RPM_SUSPENDED;
> +		spin_unlock_irq(q->queue_lock);
>  	}
> -	spin_unlock_irq(q->queue_lock);
>  }
>  EXPORT_SYMBOL(blk_post_runtime_resume);
>  #endif
>