From patchwork Fri Mar 5 15:14:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 12118653 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77DF8C433DB for ; Fri, 5 Mar 2021 15:20:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FD0F65015 for ; Fri, 5 Mar 2021 15:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229679AbhCEPTa (ORCPT ); Fri, 5 Mar 2021 10:19:30 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:12698 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229922AbhCEPTU (ORCPT ); Fri, 5 Mar 2021 10:19:20 -0500 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DsWYZ2X5XzlSk3; Fri, 5 Mar 2021 23:17:06 +0800 (CST) Received: from localhost.localdomain (10.69.192.58) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.498.0; Fri, 5 Mar 2021 23:19:07 +0800 From: John Garry To: , , , , CC: , , , , , John Garry Subject: [RFC PATCH v3 0/3] blk-mq: Avoid use-after-free for accessing old requests Date: Fri, 5 Mar 2021 23:14:51 +0800 Message-ID: <1614957294-188540-1-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This series aims to tackle the various UAF reports, like: [0] https://lore.kernel.org/linux-block/8376443a-ec1b-0cef-8244-ed584b96fa96@huawei.com/ [1] https://lore.kernel.org/linux-block/5c3ac5af-ed81-11e4-fee3-f92175f14daf@acm.org/T/#m6c1ac11540522716f645d004e2a5a13c9f218908 [2] https://lore.kernel.org/linux-block/04e2f9e8-79fa-f1cb-ab23-4a15bf3f64cc@kernel.dk/ [3] https://lore.kernel.org/linux-block/b859618aeac58bd9bb620d7ebdb24b90@codeaurora.org/ Details are in the commit messages. The issue addressed in patch 1/3 is pretty easy to reproduce, 2+3/3 not so much, and I had to add mdelays in the iters functions to recreate in sane timeframes. A regards patch 1/3, if 2+3/3 are adopted, then this can simplified to simply clear the tagset requests pointers without using any atomic operations. However, this patch on its own seems to solve the problem [3], above. So the other 2x patches are really for extreme scenarios which may never be seen in practice. As such, it could be considered to just accept patch 1/3 now. Differences to v2: - Add patch 2+3/3 - Drop patch to lockout blk_mq_queue_tag_busy_iter() when exiting elevator John Garry (3): blk-mq: Clean up references to old requests when freeing rqs blk-mq: Freeze and quiesce all queues for tagset in elevator_exit() blk-mq: Lockout tagset iterator when exiting elevator block/blk-mq-sched.c | 2 +- block/blk-mq-tag.c | 7 ++++++- block/blk-mq.c | 21 +++++++++++++++++++-- block/blk-mq.h | 2 ++ block/blk.h | 23 +++++++++++++++++++++++ include/linux/blk-mq.h | 1 + 6 files changed, 52 insertions(+), 4 deletions(-)