lkml.org 
[lkml]   [2023]   [Jul]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH -next v2 0/2] md/raid5-cache: fix a deadlock in r5l_exit_log()
From
Date
Hi,

在 2023/06/28 9:07, Yu Kuai 写道:
> From: Yu Kuai <yukuai3@huawei.com>
>
> Changes in v2:
> - remove a now unused local variable in patch 2;
>
> Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing
> work") introduce a new problem:
>
> // caller hold reconfig_mutex
> r5l_exit_log
> flush_work(&log->disable_writeback_work)
> r5c_disable_writeback_async
> wait_event
> /*
> * conf->log is not NULL, and mddev_trylock()
> * will fail, wait_event() can never pass.
> */
> conf->log = NULL
>
> patch 1 revert this patch, an patch 2 fix the original problem in a
> different way.
>
> Noted this problem is just found by code review, and I think this is
> probably the reason that some mdadm tests is broken.

Any suggestions?

By the way, while taking another look at this problem, I think probably
read and write 'conf->log' should use READ_ONCE and WRITE_ONCE.

Thanks,
Kuai
>
> Yu Kuai (2):
> md/raid5-cache: Revert "md/raid5-cache: Clear conf->log after
> finishing work"
> md/raid5-cache: fix null-ptr-deref in r5l_reclaim_thread()
>
> drivers/md/raid5-cache.c | 25 ++++++++++---------------
> 1 file changed, 10 insertions(+), 15 deletions(-)
>

\
 
 \ /
  Last update: 2023-07-07 03:24    [W:2.122 / U:3.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site