summaryrefslogtreecommitdiffstats
path: root/block
diff options
context:
space:
mode:
authorMing Lei <ming.lei@redhat.com>2022-12-15 10:16:29 +0800
committerJens Axboe <axboe@kernel.dk>2022-12-15 05:23:11 -0700
commitd36a9ea5e7766961e753ee38d4c331bbe6ef659b (patch)
tree22838399e583bfba01ccc9a22ff67791f81d40e8 /block
parent1eb206208b0f3f707c67134ef6ba394410effb67 (diff)
downloadlinux-d36a9ea5e7766961e753ee38d4c331bbe6ef659b.tar.bz2
block: fix use-after-free of q->q_usage_counter
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@huaweicloud.com> Reported-by: Zhong Jinghua <zhongjinghua@huawei.com> Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/ Cc: Hillf Danton <hdanton@sina.com> Cc: Yu Kuai <yukuai3@huawei.com> Cc: Dennis Zhou <dennis@kernel.org> Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 3866b6c4cd88..9321767470dc 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -254,14 +254,15 @@ EXPORT_SYMBOL_GPL(blk_clear_pm_only);
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
- kmem_cache_free(blk_requestq_cachep,
- container_of(rcu_head, struct request_queue, rcu_head));
+ 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);
}
static void blk_free_queue(struct request_queue *q)
{
- percpu_ref_exit(&q->q_usage_counter);
-
if (q->poll_stat)
blk_stat_remove_callback(q, q->poll_cb);
blk_stat_free_callback(q->poll_cb);