leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

blk-mq: don't add non-pt request with ->end_io to batch

Browse Source 
dm-rq implements ->end_io callback for request issued to underlying queue,
and it isn't passthrough request.

Commit ab3e1d3bba ("block: allow end_io based requests in the completion
batch handling") doesn't clear rq->bio and rq->__data_len for request
with ->end_io in blk_mq_end_request_batch(), and this way is actually
dangerous, but so far it is only for nvme passthrough request.

dm-rq needs to clean up remained bios in case of partial completion,
and req->bio is required, then use-after-free is triggered, so the
underlying clone request can't be completed in blk_mq_end_request_batch.

Fix panic by not adding such request into batch list, and the issue
can be triggered simply by exposing nvme pci to dm-mpath simply.

Fixes: ab3e1d3bba ("block: allow end_io based requests in the completion batch handling")
Cc: dm-devel@redhat.com
Cc: Mike Snitzer <snitzer@kernel.org>
Reported-by: Changhui Zhong <czhong@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20221027085709.513175-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2022-10-27 16:57:09 +08:00 committed by Jens Axboe
parent 7f21735ffb
commit 2d87d455ea
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/blk-mq.h
View File

@ -853,7 +853,8 @@ static inline bool blk_mq_add_to_batch(struct request *req,
struct io_comp_batch *iob, int ioerror,
void (*complete)(struct io_comp_batch *))
{
if (!iob || (req->rq_flags & RQF_ELV) || ioerror)
if (!iob || (req->rq_flags & RQF_ELV) || ioerror ||
(req->end_io && !blk_rq_is_passthrough(req)))
return false;
if (!iob->complete)