6.16-stable patches

added patches:
	blk-mq-fix-blk_mq_tags-double-free-while-nr_requests-grown.patch
	series

diff --git a/queue-6.16/blk-mq-fix-blk_mq_tags-double-free-while-nr_requests-grown.patch b/queue-6.16/blk-mq-fix-blk_mq_tags-double-free-while-nr_requests-grown.patch
new file mode 100644 (file)
index 0000000..c7099ee
--- /dev/null
+++ b/queue-6.16/blk-mq-fix-blk_mq_tags-double-free-while-nr_requests-grown.patch
@@ -0,0 +1,47 @@
+From ba28afbd9eff2a6370f23ef4e6a036ab0cfda409 Mon Sep 17 00:00:00 2001
+From: Yu Kuai <yukuai3@huawei.com>
+Date: Thu, 21 Aug 2025 14:06:12 +0800
+Subject: blk-mq: fix blk_mq_tags double free while nr_requests grown
+
+From: Yu Kuai <yukuai3@huawei.com>
+
+commit ba28afbd9eff2a6370f23ef4e6a036ab0cfda409 upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ block/blk-mq-tag.c |    1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/block/blk-mq-tag.c
++++ b/block/blk-mq-tag.c
+@@ -622,6 +622,7 @@ int blk_mq_tag_update_depth(struct blk_m
+                       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 {
+               /*

diff --git a/queue-6.16/series b/queue-6.16/series
new file mode 100644 (file)
index 0000000..c47cccf
--- /dev/null
+++ b/queue-6.16/series
@@ -0,0 +1 @@
+blk-mq-fix-blk_mq_tags-double-free-while-nr_requests-grown.patch