This is a note to let you know that I've just added the patch titled
block: fix use-after-free of q->q_usage_counter
to the 5.10-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:
block-fix-use-after-free-of-q-q_usage_counter.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d36a9ea5e7766961e753ee38d4c331bbe6ef659b Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@xxxxxxxxxx>
Date: Thu, 15 Dec 2022 10:16:29 +0800
Subject: block: fix use-after-free of q->q_usage_counter
From: Ming Lei <ming.lei@xxxxxxxxxx>
commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b upstream.
For blk-mq, queue release handler is usually called after
blk_mq_freeze_queue_wait() returns. However, the
q_usage_counter->release() handler may not be run yet at that time, so
this can cause a use-after-free.
Fix the issue by moving percpu_ref_exit() into blk_free_queue_rcu().
Since ->release() is called with rcu read lock held, it is agreed that
the race should be covered in caller per discussion from the two links.
Reported-by: Zhang Wensheng <zhangwensheng@xxxxxxxxxxxxxxx>
Reported-by: Zhong Jinghua <zhongjinghua@xxxxxxxxxx>
Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u
Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Yu Kuai <yukuai3@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Saranya Muruganandam <saranyamohan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-core.c | 2 --
block/blk-sysfs.c | 2 ++
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -414,8 +414,6 @@ void blk_cleanup_queue(struct request_qu
blk_mq_sched_free_requests(q);
mutex_unlock(&q->sysfs_lock);
- percpu_ref_exit(&q->q_usage_counter);
-
/* @q is and will stay empty, shutdown and put */
blk_put_queue(q);
}
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -726,6 +726,8 @@ static void blk_free_queue_rcu(struct rc
{
struct request_queue *q = container_of(rcu_head, struct request_queue,
rcu_head);
+
+ percpu_ref_exit(&q->q_usage_counter);
kmem_cache_free(blk_requestq_cachep, q);
}
Patches currently in stable-queue which might be from ming.lei@xxxxxxxxxx are
queue-5.10/block-fix-use-after-free-of-q-q_usage_counter.patch
