This is a note to let you know that I've just added the patch titled
blk-mq: fix tags leak when shrink nr_hw_queues
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blk-mq-fix-tags-leak-when-shrink-nr_hw_queues.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 27a486968e71cda6512269f614fd4ec685755bbd
Author: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Date: Mon Aug 21 17:56:00 2023 +0800
blk-mq: fix tags leak when shrink nr_hw_queues
[ Upstream commit e1dd7bc93029024af5688253b0c05181d6e01f8e ]
Although we don't need to realloc set->tags[] when shrink nr_hw_queues,
we need to free them. Or these tags will be leaked.
How to reproduce:
1. mount -t configfs configfs /mnt
2. modprobe null_blk nr_devices=0 submit_queues=8
3. mkdir /mnt/nullb/nullb0
4. echo 1 > /mnt/nullb/nullb0/power
5. echo 4 > /mnt/nullb/nullb0/submit_queues
6. rmdir /mnt/nullb/nullb0
In step 4, will alloc 9 tags (8 submit queues and 1 poll queue), then
in step 5, new_nr_hw_queues = 5 (4 submit queues and 1 poll queue).
At last in step 6, only these 5 tags are freed, the other 4 tags leaked.
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230821095602.70742-1-chengming.zhou@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 953f08354c8c3..d9b365c2eaa0d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4402,9 +4402,13 @@ static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
int new_nr_hw_queues)
{
struct blk_mq_tags **new_tags;
+ int i;
- if (set->nr_hw_queues >= new_nr_hw_queues)
+ if (set->nr_hw_queues >= new_nr_hw_queues) {
+ for (i = new_nr_hw_queues; i < set->nr_hw_queues; i++)
+ __blk_mq_free_map_and_rqs(set, i);
goto done;
+ }
new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
GFP_KERNEL, set->numa_node);
