Commit 90d1a836 authored by Zhang Yi's avatar Zhang Yi Committed by Zheng Zengkai
Browse files

dm: make sure dm_table is binded before queue request 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4U3RI


CVE: NA

--------------------------------

We found a NULL pointer dereference problem when using dm-mpath target.
The problem is if we submit IO between loading and binding the table,
we could neither get a valid dm_target nor a valid dm table when
submitting request in dm_mq_queue_rq(). BIO based dm target could
handle this case in dm_submit_bio(). This patch fix this by checking
the mapping table before submitting request.

Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Reviewed-by: default avatarJason Yan <yanaijie@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 39adeffc

drivers/md/dm-rq.c

+9 −2
Original line number Diff line number Diff line
@@ -492,8 +492,15 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 


	if (unlikely(!ti)) {

		int srcu_idx;

		struct dm_table *map = dm_get_live_table(md, &srcu_idx);

		struct dm_table *map;



		map = dm_get_live_table(md, &srcu_idx);

		if (!map) {

			DMERR_LIMIT("%s: mapping table unavailable, erroring io",

				    dm_device_name(md));

			dm_put_live_table(md, srcu_idx);

			return BLK_STS_IOERR;

		}

		ti = dm_table_find_target(map, 0);

		dm_put_live_table(md, srcu_idx);

	}