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From: Song Liu <song@kernel.org>
To: Junxiao Bi <junxiao.bi@oracle.com>
Cc: linux-raid <linux-raid@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] md: fix deadlock causing by sysfs_notify
Date: Mon, 13 Jul 2020 23:17:28 -0700	[thread overview]
Message-ID: <CAPhsuW7seCUnt3zt6A_fjTS2diB7qiTE+SZkM6Vh=G26hdwGtg@mail.gmail.com> (raw)
In-Reply-To: <20200709233545.67954-1-junxiao.bi@oracle.com>

On Thu, Jul 9, 2020 at 4:36 PM Junxiao Bi <junxiao.bi@oracle.com> wrote:
>
> The following deadlock was captured. The first process is holding 'kernfs_mutex'
> and hung by io. The io was staging in 'r1conf.pending_bio_list' of raid1 device,
> this pending bio list would be flushed by second process 'md127_raid1', but
> it was hung by 'kernfs_mutex'. Using sysfs_notify_dirent_safe() to replace
> sysfs_notify() can fix it. There were other sysfs_notify() invoked from io
> path, removed all of them.
>
[...]
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>

Thanks for the patch. It looks good in general. One question though, do we
need the same change the following line in md.c:level_store()?

    sysfs_notify(&mddev->kobj, NULL, "level");

Thanks,
Song

[...]

  parent reply	other threads:[~2020-07-14  6:17 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09 23:35 [PATCH] md: fix deadlock causing by sysfs_notify Junxiao Bi
2020-07-13 18:49 ` Junxiao Bi
2020-07-16 17:21   ` Vitaly Mayatskih
2020-07-14  6:17 ` Song Liu [this message]
2020-07-14  6:41   ` Junxiao Bi
2020-07-14 16:18     ` Song Liu
2020-07-14 16:29       ` Junxiao Bi

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