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| author | Yu Kuai <yukuai3@huawei.com> | 2023-07-08 17:17:27 +0800 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-08-15 09:37:27 -0700 |
| commit | a705b11b358dee677aad80630e7608b2d5f56691 (patch) | |
| tree | f9beddaeaf22c8aad64f734715b0c6a28d84464b /drivers | |
| parent | 66a6a5d0ec852eaced589da066376e69397cd71e (diff) | |
| download | linux-stable-a705b11b358dee677aad80630e7608b2d5f56691.tar.gz linux-stable-a705b11b358dee677aad80630e7608b2d5f56691.tar.bz2 linux-stable-a705b11b358dee677aad80630e7608b2d5f56691.zip | |
md/raid5-cache: fix a deadlock in r5l_exit_log()
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
Fix this problem by setting 'config->log' to NULL before wake_up() as it
used to be, so that wait_event() from r5c_disable_writeback_async() can
exist. In the meantime, move forward md_unregister_thread() so that
null-ptr-deref this commit fixed can still be fixed.
Fixes: b13015af94cf ("md/raid5-cache: Clear conf->log after finishing work")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20230708091727.1417894-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/raid5-cache.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 47ba7d9e81e1..2eac4a50d99b 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -3168,12 +3168,15 @@ void r5l_exit_log(struct r5conf *conf) { struct r5l_log *log = conf->log; - /* Ensure disable_writeback_work wakes up and exits */ - wake_up(&conf->mddev->sb_wait); - flush_work(&log->disable_writeback_work); md_unregister_thread(&log->reclaim_thread); + /* + * 'reconfig_mutex' is held by caller, set 'confg->log' to NULL to + * ensure disable_writeback_work wakes up and exits. + */ conf->log = NULL; + wake_up(&conf->mddev->sb_wait); + flush_work(&log->disable_writeback_work); mempool_exit(&log->meta_pool); bioset_exit(&log->bs); |