md/raid10: fix null-ptr-deref of mreplace in raid10_sync_request

[ Upstream commit 34817a2441 ]

There are two check of 'mreplace' in raid10_sync_request(). In the first
check, 'need_replace' will be set and 'mreplace' will be used later if
no-Faulty 'mreplace' exists, In the second check, 'mreplace' will be
set to NULL if it is Faulty, but 'need_replace' will not be changed
accordingly. null-ptr-deref occurs if Faulty is set between two check.

Fix it by merging two checks into one. And replace 'need_replace' with
'mreplace' because their values are always the same.

Fixes: ee37d7314a ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527072218.2365857-2-linan666@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Li Nan 2023-05-27 15:22:15 +08:00 committed by Greg Kroah-Hartman
parent 3c76920e54
commit f4368a462b

View File

@ -3412,7 +3412,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
int must_sync;
int any_working;
int need_recover = 0;
int need_replace = 0;
struct raid10_info *mirror = &conf->mirrors[i];
struct md_rdev *mrdev, *mreplace;
@ -3424,11 +3423,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
!test_bit(Faulty, &mrdev->flags) &&
!test_bit(In_sync, &mrdev->flags))
need_recover = 1;
if (mreplace != NULL &&
!test_bit(Faulty, &mreplace->flags))
need_replace = 1;
if (mreplace && test_bit(Faulty, &mreplace->flags))
mreplace = NULL;
if (!need_recover && !need_replace) {
if (!need_recover && !mreplace) {
rcu_read_unlock();
continue;
}
@ -3444,8 +3442,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
rcu_read_unlock();
continue;
}
if (mreplace && test_bit(Faulty, &mreplace->flags))
mreplace = NULL;
/* Unless we are doing a full sync, or a replacement
* we only need to recover the block if it is set in
* the bitmap
@ -3568,11 +3564,11 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bio = r10_bio->devs[1].repl_bio;
if (bio)
bio->bi_end_io = NULL;
/* Note: if need_replace, then bio
/* Note: if replace is not NULL, then bio
* cannot be NULL as r10buf_pool_alloc will
* have allocated it.
*/
if (!need_replace)
if (!mreplace)
break;
bio->bi_next = biolist;
biolist = bio;