From: Li Nan linan122@huawei.com
commit a405c6f0229526160aa3f177f65e20c86fce84c5 upstream.
init_resync() inits mempool and sets conf->have_replacemnt at the beginning of sync, close_sync() frees the mempool when sync is completed.
After [1] recovery might be skipped and init_resync() is called but close_sync() is not. null-ptr-deref occurs with r10bio->dev[i].repl_bio.
The following is one way to reproduce the issue.
1) create a array, wait for resync to complete, mddev->recovery_cp is set to MaxSector. 2) recovery is woken and it is skipped. conf->have_replacement is set to 0 in init_resync(). close_sync() not called. 3) some io errors and rdev A is set to WantReplacement. 4) a new device is added and set to A's replacement. 5) recovery is woken, A have replacement, but conf->have_replacemnt is 0. r10bio->dev[i].repl_bio will not be alloced and null-ptr-deref occurs.
Fix it by not calling init_resync() if recovery skipped.
[1] commit 7e83ccbecd60 ("md/raid10: Allow skipping recovery when clean arrays are assembled") Fixes: 7e83ccbecd60 ("md/raid10: Allow skipping recovery when clean arrays are assembled") Cc: stable@vger.kernel.org Signed-off-by: Li Nan linan122@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20230222041000.3341651-3-linan666@huaweicloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/raid10.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2957,10 +2957,6 @@ static sector_t raid10_sync_request(stru sector_t chunk_mask = conf->geo.chunk_mask; int page_idx = 0;
- if (!mempool_initialized(&conf->r10buf_pool)) - if (init_resync(conf)) - return 0; - /* * Allow skipping a full rebuild for incremental assembly * of a clean array, like RAID1 does. @@ -2976,6 +2972,10 @@ static sector_t raid10_sync_request(stru return mddev->dev_sectors - sector_nr; }
+ if (!mempool_initialized(&conf->r10buf_pool)) + if (init_resync(conf)) + return 0; + skipped: max_sector = mddev->dev_sectors; if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||