lkml.org 
[lkml]   [2020]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] md: fix deadlock causing by sysfs_notify
From
Date
On 7/13/20 11:17 PM, Song Liu wrote:

> 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 for the review. This one is not in io path, looks it's safe. I
can change it if you want to align it with others.

Thanks,

Junxiao.

>
> Thanks,
> Song
>
> [...]

\
 
 \ /
  Last update: 2020-07-14 08:41    [W:0.085 / U:0.428 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site