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 X-Spam-Level: X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 F0AD3C47082 for ; Tue, 8 Jun 2021 07:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C819061287 for ; Tue, 8 Jun 2021 07:19:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229526AbhFHHVQ (ORCPT ); Tue, 8 Jun 2021 03:21:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49940 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbhFHHVP (ORCPT ); Tue, 8 Jun 2021 03:21:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623136763; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=JKRRC84E0OIYQ/P5AoK+syWxBWg0gWjtBYn62R6KGdo=; b=VJM2Mco6xYr3c3n07Il25/dcMfDLbzpI2AYNQQ/zjHEUf8GOXvJ7z0zHXMTIzkMNP1/hYe qtiBHteH6lzFjcRT868x92mXtRCBUxjDnun7KxkJghv8ZTWcQ7b7x0v8JxDpvaZB98lEFL 0xaEGZNuhAhxktu/fr0fUWpzV8SZ0go= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-426-kPhUXU7iPi-fN4wXnSQH4g-1; Tue, 08 Jun 2021 03:19:21 -0400 X-MC-Unique: kPhUXU7iPi-fN4wXnSQH4g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E95A88049C5; Tue, 8 Jun 2021 07:19:20 +0000 (UTC) Received: from localhost (ovpn-12-142.pek2.redhat.com [10.72.12.142]) by smtp.corp.redhat.com (Postfix) with ESMTP id BA38D19C66; Tue, 8 Jun 2021 07:19:13 +0000 (UTC) From: Ming Lei To: Jens Axboe , Christoph Hellwig Cc: linux-block@vger.kernel.org, Ming Lei , Yi Zhang , Bart Van Assche Subject: [PATCH V2 0/2] block: fix race between adding wbt and normal IO Date: Tue, 8 Jun 2021 15:19:01 +0800 Message-Id: <20210608071903.431195-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hello, Yi reported several kernel panics on: [16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 ... [16687.163549] pc : __rq_qos_track+0x38/0x60 or [ 997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... [ 997.850347] pc : __rq_qos_done+0x2c/0x50 Turns out it is caused by race between adding wbt and normal IO. Fix the issue by freezing request queue when adding/deleting rq qos. V2: - switch to the approach of freezing queue, which is more generic than V1. Ming Lei (2): block: fix race between adding/removing rq qos and normal IO block: mark queue init done at the end of blk_register_queue block/blk-rq-qos.h | 13 +++++++++++++ block/blk-sysfs.c | 29 +++++++++++++++-------------- 2 files changed, 28 insertions(+), 14 deletions(-) Cc: Yi Zhang Cc: Bart Van Assche -- 2.31.1