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Commit 45fa023b authored by Li Nan's avatar Li Nan Committed by Greg Kroah-Hartman
Browse files

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



[ Upstream commit 34817a2441747b48e444cb0e05d84e14bc9443da ]

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: ee37d731 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: default avatarLi Nan <linan122@huawei.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527072218.2365857-2-linan666@huaweicloud.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 31c805a4

drivers/md/raid10.c

+5 −9
Original line number Diff line number Diff line
@@ -3054,7 +3054,6 @@ 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;
@@ -3066,11 +3065,10 @@ 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;

			}
@@ -3086,8 +3084,6 @@ 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
@@ -3210,11 +3206,11 @@ 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;