Re: [PATCH v5 06/14] md: fix missing release of 'active_io' for flush

[Song Liu]

On Thu, Feb 1, 2024 at 1:30 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> submit_flushes
>  atomic_set(&mddev->flush_pending, 1);
>  rdev_for_each_rcu(rdev, mddev)
>   atomic_inc(&mddev->flush_pending);
>   bi->bi_end_io = md_end_flush
>   submit_bio(bi);
>                         /* flush io is done first */
>                         md_end_flush
>                          if (atomic_dec_and_test(&mddev->flush_pending))
>                           percpu_ref_put(&mddev->active_io)
>                           -> active_io is not released
>
>  if (atomic_dec_and_test(&mddev->flush_pending))
>   -> missing release of active_io
>
> For consequence, mddev_suspend() will wait for 'active_io' to be zero
> forever.
>
> Fix this problem by releasing 'active_io' in submit_flushes() if
> 'flush_pending' is decreased to zero.
>
> Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration")
> Reported-by: Blazej Kucman <blazej.kucman@xxxxxxxxxxxxxxx>
> Closes: https://lore.kernel.org/lkml/20240130172524.0000417b@xxxxxxxxxxxxxxx/
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>

Applied this patch to md-6.8.

Thanks,
Song