diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2025-08-21 14:06:12 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-09-05 13:52:52 -0600 |
| commit | ba28afbd9eff2a6370f23ef4e6a036ab0cfda409 (patch) | |
| tree | a06c5203bd19528d03cb460e6477dc646b359e98 | |
| parent | 7d337eef4affc5e26e0570513168c69ddbc40f92 (diff) | |
blk-mq: fix blk_mq_tags double free while nr_requests grown
In the case user trigger tags grow by queue sysfs attribute nr_requests,
hctx->sched_tags will be freed directly and replaced with a new
allocated tags, see blk_mq_tag_update_depth().
The problem is that hctx->sched_tags is from elevator->et->tags, while
et->tags is still the freed tags, hence later elevator exit will try to
free the tags again, causing kernel panic.
Fix this problem by replacing et->tags with new allocated tags as well.
Noted there are still some long term problems that will require some
refactor to be fixed thoroughly[1].
[1] https://lore.kernel.org/all/20250815080216.410665-1-yukuai1@huaweicloud.com/
Fixes: f5a6604f7a44 ("block: fix lockdep warning caused by lock dependency in elv_iosched_store")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Li Nan <linan122@huawei.com>
Link: https://lore.kernel.org/r/20250821060612.1729939-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-mq-tag.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index d880c50629d6..5cffa5668d0c 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -622,6 +622,7 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, return -ENOMEM; blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num); + hctx->queue->elevator->et->tags[hctx->queue_num] = new; *tagsptr = new; } else { /* |