From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AEEEC54EE9 for ; Tue, 13 Sep 2022 04:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229980AbiIMETD (ORCPT ); Tue, 13 Sep 2022 00:19:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229967AbiIMESx (ORCPT ); Tue, 13 Sep 2022 00:18:53 -0400 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBB7C5467D; Mon, 12 Sep 2022 21:18:50 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R251e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=ziyangzhang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VPccyDn_1663042725; Received: from localhost.localdomain(mailfrom:ZiyangZhang@linux.alibaba.com fp:SMTPD_---0VPccyDn_1663042725) by smtp.aliyun-inc.com; Tue, 13 Sep 2022 12:18:48 +0800 From: ZiyangZhang To: ming.lei@redhat.com Cc: axboe@kernel.dk, xiaoguang.wang@linux.alibaba.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com, ZiyangZhang Subject: [PATCH V3 2/7] ublk_drv: refactor ublk_cancel_queue() Date: Tue, 13 Sep 2022 12:17:02 +0800 Message-Id: <20220913041707.197334-3-ZiyangZhang@linux.alibaba.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220913041707.197334-1-ZiyangZhang@linux.alibaba.com> References: <20220913041707.197334-1-ZiyangZhang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Assume only a few FETCH_REQ ioucmds are sent to ublk_drv, then the ubq_daemon exits, We have to call io_uring_cmd_done() for all ioucmds received so that io_uring ctx will not leak. ublk_cancel_queue() may be called before START_DEV or after STOP_DEV, we decrease ubq->nr_io_ready and clear UBLK_IO_FLAG_ACTIVE so that we won't call io_uring_cmd_done() twice for one ioucmd to avoid UAF. Also clearing UBLK_IO_FLAG_ACTIVE makes the code more reasonable. Signed-off-by: ZiyangZhang Reviewed-by: Ming Lei --- drivers/block/ublk_drv.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index c39b67d7133d..0c6db0978ed0 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -963,22 +963,39 @@ static inline bool ublk_queue_ready(struct ublk_queue *ubq) return ubq->nr_io_ready == ubq->q_depth; } +/* If ublk_cancel_queue() is called before sending START_DEV(), ->mutex + * provides protection on above update. + * + * If ublk_cancel_queue() is called after sending START_DEV(), disk is + * deleted first, UBLK_IO_RES_ABORT is returned so that any new io + * command can't be issued to driver, so updating on io flags and + * nr_io_ready is safe here. + * + * Also ->nr_io_ready is guaranteed to become zero after ublk_cance_queue() + * returns since request queue is either frozen or not present in both two + * cases. + */ static void ublk_cancel_queue(struct ublk_queue *ubq) { int i; - if (!ublk_queue_ready(ubq)) + if (!ubq->nr_io_ready) return; for (i = 0; i < ubq->q_depth; i++) { struct ublk_io *io = &ubq->ios[i]; - if (io->flags & UBLK_IO_FLAG_ACTIVE) + if (io->flags & UBLK_IO_FLAG_ACTIVE) { + pr_devel("%s: done old cmd: qid %d tag %d\n", + __func__, ubq->q_id, i); io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0); + io->flags &= ~UBLK_IO_FLAG_ACTIVE; + ubq->nr_io_ready--; + } } /* all io commands are canceled */ - ubq->nr_io_ready = 0; + WARN_ON_ONCE(ubq->nr_io_ready); } /* Cancel all pending commands, must be called after del_gendisk() returns */ -- 2.27.0