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 6648F1A5A4 for ; Mon, 9 Oct 2023 13:24:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xBlU8eBc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4DD0C433CB; Mon, 9 Oct 2023 13:24:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696857862; bh=UWDlm2c3sxrfhBNwdv6J+jPDuXDlWyI555a8DnjkTLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xBlU8eBc4mBQDtcuk1QrGY/c+YMNJLvvM5RWj6TFO1VGfVNvoI2QvY1lTC3046+KE cfClPl3wVCZR99iS23lAuUx8sJbCldQmQbMPNFGJMmBmDAaqrnlNVc9WEKhRgfnrvV oyAvTkabGn3vbOJD2CEshh+UPHEz65z0i5cDosf0= 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 5.15 17/75] block: fix use-after-free of q->q_usage_counter Date: Mon, 9 Oct 2023 15:01:39 +0200 Message-ID: <20231009130111.837326975@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130111.200710898@linuxfoundation.org> References: <20231009130111.200710898@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 5.15-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-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 @@ -405,8 +405,6 @@ 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 @@ -748,6 +748,8 @@ 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); }