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 B2EC11A596 for ; Mon, 9 Oct 2023 13:18:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XU0YFG1P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DC42C433C7; Mon, 9 Oct 2023 13:18:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696857534; bh=C7yM5o69/xxrFDbNbTCbfdjl4vX4Owf/faeL9kjUBRM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XU0YFG1P+aNw+yVuWBZ6yXzYVokmc/7EIpO327d6jaRVtlYTnFlVzr1BE35oulhNj YQh+GXOgg8chhghutnzx/RXV/0Pbfwlc5cis8MwWVRe6fQj7ikM5JSl1x+DXPSD8dL vWKfYlllgmlYquM9g98dCBMvwvGOI1t2W+vVgdIo= 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 , Saranya Muruganandam Subject: [PATCH 6.1 050/162] block: fix use-after-free of q->q_usage_counter Date: Mon, 9 Oct 2023 15:00:31 +0200 Message-ID: <20231009130124.320135372@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130122.946357448@linuxfoundation.org> References: <20231009130122.946357448@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei 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 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: Saranya Muruganandam Signed-off-by: Greg Kroah-Hartman --- block/blk-sysfs.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -737,6 +737,7 @@ 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_get_queue_kmem_cache(blk_queue_has_srcu(q)), q); } @@ -762,8 +763,6 @@ static void blk_release_queue(struct kob might_sleep(); - 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);