From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 626981C08 for ; Wed, 28 Dec 2022 16:34:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC550C433D2; Wed, 28 Dec 2022 16:34:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245244; bh=DsO4oshAoyrE2z27EaNBuTJqZRv2ZkjUpeyIWUp5rdA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p07G8FEMQ5CY//uPK79jor2jEzdKEAebyKX4Pa8AkmU9i/ile1ZMJey7OWOg3WJs4 12vedLuT9CBK7Bm66tL+GGdV0fu3sFAxwAOmzOuQAKnsJb+rZIm+dnKIEBD7MtgAnP d1z+3C4eW+1xhpCwSbP6FMif//+IMn0fyk+N/sks= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhang Wensheng , Zhong Jinghua , Hillf Danton , Yu Kuai , Dennis Zhou , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 6.0 0859/1073] block: fix use-after-free of q->q_usage_counter Date: Wed, 28 Dec 2022 15:40:47 +0100 Message-Id: <20221228144351.350701784@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144328.162723588@linuxfoundation.org> References: <20221228144328.162723588@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ming Lei [ Upstream commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b ] 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 Reported-by: Zhong Jinghua Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/ Cc: Hillf Danton Cc: Yu Kuai Cc: Dennis Zhou Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-core.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 818002b8be7c..3459fe316a34 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -255,14 +255,15 @@ 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); -- 2.35.1