summaryrefslogtreecommitdiff
path: root/drivers/md
diff options
context:
space:
mode:
authorYu Kuai <yukuai3@huawei.com>2023-07-08 12:17:27 +0300
committerSong Liu <song@kernel.org>2023-08-15 19:37:27 +0300
commita705b11b358dee677aad80630e7608b2d5f56691 (patch)
treef9beddaeaf22c8aad64f734715b0c6a28d84464b /drivers/md
parent66a6a5d0ec852eaced589da066376e69397cd71e (diff)
downloadlinux-a705b11b358dee677aad80630e7608b2d5f56691.tar.xz
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/md')
-rw-r--r--drivers/md/raid5-cache.c9
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);