From: Ming Lei ming.lei@redhat.com
mainline inclusion from mainline-v6.2-rc1 commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b category: bugfix bugzilla: 187268, https://gitee.com/openeuler/kernel/issues/I5N162
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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
conflicts: block/blk-sysfs.c block/blk-core.c
Signed-off-by: Zhong Jinghua zhongjinghua@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- block/blk-sysfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 35cd1df55680..169e63ee05cb 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -726,6 +726,8 @@ static void blk_free_queue_rcu(struct rcu_head *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); }
@@ -784,8 +786,6 @@ static void blk_release_queue(struct kobject *kobj)
might_sleep();
- percpu_ref_exit(&q->q_usage_counter); - if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags)) blk_stat_remove_callback(q, q->poll_cb); blk_stat_free_callback(q->poll_cb);