From a405c6f0229526160aa3f177f65e20c86fce84c5 Mon Sep 17 00:00:00 2001
From: Li Nan <linan122@huawei.com>
Date: Wed, 22 Feb 2023 12:10:00 +0800
Subject: [PATCH] md/raid10: fix null-ptr-deref in raid10_sync_request
Git-commit: a405c6f0229526160aa3f177f65e20c86fce84c5
Patch-mainline: v6.4-rc1
References: git-fixes
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")
(Coly Li: rebased for Linux 4.12 based SUSE kernel)
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: Coly Li <colyli@suse.de>
---
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 (!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 (!conf->r10buf_pool)
+ if (init_resync(conf))
+ return 0;
+
skipped:
max_sector = mddev->dev_sectors;
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||