From patchwork Thu Apr 13 11:32:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 82928 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp967673vqo; Thu, 13 Apr 2023 04:43:47 -0700 (PDT) X-Google-Smtp-Source: AKy350ZAE2PEAcjkKkcSRsb1heiNEFGiRJzP4jeFSPSlpRX/hvKBQt9IdA90frUblMz1gKLVTox+ X-Received: by 2002:a17:902:ecca:b0:1a2:9334:f79a with SMTP id a10-20020a170902ecca00b001a29334f79amr2270828plh.38.1681386226807; Thu, 13 Apr 2023 04:43:46 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681386226; cv=none; d=google.com; s=arc-20160816; b=bpRwnL+snkIqQiU/kuFtZdrP1sVWQ1RmP5oTJKBFrbAQGm0Skvb2SLZrJpXMTEd5Ks 0dgOZL7pDfIIkJU9yrv39DTveB84G0jVZaTyYKleYq2Cjf7wPRLsygjDPgl30tEMjx0t V3A93UKDIApM1D7Nq23ZN/34rMVdjdWqKf8s0R2y+RNE2wpH7qHx3rgnR9Lpw+0NMlpo BxvoGTmra38H9NtcGW2I3xaPlbwM+cwjAfiw3dAH6RT0VAY26qr5bcKN0mUKHfmjv30r KeQvAp8bTsEXPk5Z1XaDn3IsBub1Ts+qlkv9PkZ6o5wvDL+rHYW7uintHw7ColQBgnGz 0+aw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=BwN6khv/5HG+AhmODXqw7+UFcM/9AzoJd7assW2CnpY=; b=a6LFXyZkmLwYcyrO8yxrp+aeaLo/u1yznLe5+OTLNYQ5FW30+97SVVtmVfxWaSNc6J qhlQGTgtYQ1ii/lK1/ANGKHrzgD0DpJxc8+1dwElu+rB2tJE4E7a8yf8ikn7JmGjVl8F HHI+BXcGmmsfLWGUfAO7sONiQ9D8LT5Y2UygvxzEAb0p/49vRuFadeLTslvItHbkpiSz hYb9HMhaRj01Gf3HTiIn1kr9U04qtaUnCpgr8sOYdv6OPHr8EfKY627J2lJwhfAjgky7 4N0oqiXlBhva9YDJka1pdSwyrFk4GLkuRvS6oSMFHcBOuZu2Tjjv8hlAj+r3v+QYmHe4 VdzA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id u2-20020a17090282c200b001a6555fb909si1848916plz.183.2023.04.13.04.43.34; Thu, 13 Apr 2023 04:43:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230495AbjDMLdj (ORCPT + 99 others); Thu, 13 Apr 2023 07:33:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230364AbjDMLd3 (ORCPT ); Thu, 13 Apr 2023 07:33:29 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0130DE; Thu, 13 Apr 2023 04:33:25 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4PxyBT1KdHz4f4nX3; Thu, 13 Apr 2023 19:33:21 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgCH77KA6DdkC6FCHQ--.33135S5; Thu, 13 Apr 2023 19:33:22 +0800 (CST) From: Yu Kuai To: dm-devel@redhat.com, song@kernel.org, logang@deltatee.com Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH -next v6 1/5] md: factor out a helper to wake up md_thread directly Date: Thu, 13 Apr 2023 19:32:13 +0800 Message-Id: <20230413113217.1934353-2-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230413113217.1934353-1-yukuai1@huaweicloud.com> References: <20230413113217.1934353-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgCH77KA6DdkC6FCHQ--.33135S5 X-Coremail-Antispam: 1UD129KBjvJXoWxXFW8CF17JrW5Xr1kKF4xtFb_yoW5CFW3p3 y8tF15Wr48ZFZxZFZrJa4DCa4rZr10qFy7try7Cw4rJw1rKw43tFyS9FyjyFyDAFyrAw45 Zw15tFWrurZ2kr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9q14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r1I6r4UM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1l84 ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I2 62IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcV AFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG 0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1l42xK82IYc2Ij64vIr41l4I8I3I 0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWU GVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI 0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0 rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r 4UJbIYCTnIWIevJa73UjIFyTuYvjfU5SoXUUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1763061244450037768?= X-GMAIL-MSGID: =?utf-8?q?1763061244450037768?= From: Yu Kuai md_wakeup_thread() can't wakeup md_thread->tsk if md_thread->run is still in progress, and in some cases md_thread->tsk need to be woke up directly, like md_set_readonly() and do_md_stop(). Commit 9dfbdafda3b3 ("md: unlock mddev before reap sync_thread in action_store") introduce a new scenario where unregister sync_thread is not protected by 'reconfig_mutex', this can cause null-ptr-deference in theroy: t1: md_set_readonly t2: action_store md_unregister_thread // 'reconfig_mutex' is not held // 'reconfig_mutex' is held by caller if (mddev->sync_thread) thread = *threadp *threadp = NULL wake_up_process(mddev->sync_thread->tsk) // null-ptr-deference This patch factor out a helper to wake up md_thread directly, so that 'sync_thread' won't be accessed multiple times from the reader side. And perhaps this helper will be used later to fix action_store(). This patch also prepare to protect md_thread with rcu. Signed-off-by: Yu Kuai --- drivers/md/md.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 9bc05f451d42..e3c30500bd15 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -92,6 +92,7 @@ static struct workqueue_struct *md_rdev_misc_wq; static int remove_and_add_spares(struct mddev *mddev, struct md_rdev *this); static void mddev_detach(struct mddev *mddev); +static void md_wakeup_thread_directly(struct md_thread *thread); enum md_ro_state { MD_RDWR, @@ -6269,10 +6270,12 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev) } if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) set_bit(MD_RECOVERY_INTR, &mddev->recovery); - if (mddev->sync_thread) - /* Thread might be blocked waiting for metadata update - * which will now never happen */ - wake_up_process(mddev->sync_thread->tsk); + + /* + * Thread might be blocked waiting for metadata update which will now + * never happen + */ + md_wakeup_thread_directly(mddev->sync_thread); if (mddev->external && test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) return -EBUSY; @@ -6333,10 +6336,12 @@ static int do_md_stop(struct mddev *mddev, int mode, } if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) set_bit(MD_RECOVERY_INTR, &mddev->recovery); - if (mddev->sync_thread) - /* Thread might be blocked waiting for metadata update - * which will now never happen */ - wake_up_process(mddev->sync_thread->tsk); + + /* + * Thread might be blocked waiting for metadata update which will now + * never happen + */ + md_wakeup_thread_directly(mddev->sync_thread); mddev_unlock(mddev); wait_event(resync_wait, (mddev->sync_thread == NULL && @@ -7886,6 +7891,12 @@ static int md_thread(void *arg) return 0; } +static void md_wakeup_thread_directly(struct md_thread *thread) +{ + if (thread) + wake_up_process(thread->tsk); +} + void md_wakeup_thread(struct md_thread *thread) { if (thread) {