From patchwork Thu Feb 20 02:44:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 11393085 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 71D2B1580 for ; Thu, 20 Feb 2020 02:44:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CD1324676 for ; Thu, 20 Feb 2020 02:44:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727921AbgBTCox (ORCPT ); Wed, 19 Feb 2020 21:44:53 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:43094 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727515AbgBTCox (ORCPT ); Wed, 19 Feb 2020 21:44:53 -0500 Received: by mail-pg1-f194.google.com with SMTP id u12so1133368pgb.10 for ; Wed, 19 Feb 2020 18:44:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VHzHniqW9FZF1qhMp65mKq0FyUT0hhSij2tHk+/E1cg=; b=Y66X6E6XEZI/0df9uutcNbZlHauE4KPTlF1h+L//uHonJC3TDwrsDMLUFJRz1r7VDC bL8qZD4hOFNg4aVgLFLefIzQR8cbN9n3QvlCMjuyEhSjteBnX46KoJ66J92F9rdYmQ6V sG5xPEJ6Iu73KxS4N0CUIE2f5ePqZNHRH4A1vIrNImoAWNsmQC+Iey9+fd7Gh4qg8Yy5 /JfVP0VCanFZ9Fe7P/LAn+gSjrRgzd5Bhf433SdWsO6BU0e4Zlae8MCLvalo7PWpARpk eYNNDedMSIdk5ez0WsvQY9fkzVvCjWRL+e0zWU70XEkZbJd+WjMcXGKyLNtN8/W5DKYA fIDA== X-Gm-Message-State: APjAAAWIUws8dDDooOhHG/JoQgxgnAwjuFB1PmX4l9ab6GC0LASoMpFz cRGiMu7AWAq8CQ8K8HuyPII= X-Google-Smtp-Source: APXvYqw5R5nzsc/wBnbG50HtmHcuvppit5Ke+Pua1QL7LncsUjQz87Ak3mMUBfv2e6c84UsgG6QoQA== X-Received: by 2002:a63:348b:: with SMTP id b133mr31194547pga.372.1582166691423; Wed, 19 Feb 2020 18:44:51 -0800 (PST) Received: from asus.hsd1.ca.comcast.net ([2601:647:4000:d7:29a7:b1bb:5b40:3d61]) by smtp.gmail.com with ESMTPSA id t23sm1005466pfq.6.2020.02.19.18.44.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Feb 2020 18:44:50 -0800 (PST) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Bart Van Assche , Ming Lei , Christoph Hellwig , Hannes Reinecke , Johannes Thumshirn , Keith Busch Subject: [PATCH v2 3/8] blk-mq: Fix a recently introduced regression in blk_mq_realloc_hw_ctxs() Date: Wed, 19 Feb 2020 18:44:36 -0800 Message-Id: <20200220024441.11558-4-bvanassche@acm.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200220024441.11558-1-bvanassche@acm.org> References: <20200220024441.11558-1-bvanassche@acm.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org q->nr_hw_queues must only be updated once it is known that blk_mq_realloc_hw_ctxs() has succeeded. Otherwise it can happen that reallocation fails and that q->nr_hw_queues is larger than the number of allocated hardware queues. This patch fixes the following crash if increasing the number of hardware queues fails: BUG: KASAN: null-ptr-deref in blk_mq_map_swqueue+0x775/0x810 Write of size 8 at addr 0000000000000118 by task check/977 CPU: 3 PID: 977 Comm: check Not tainted 5.6.0-rc1-dbg+ #8 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack+0xa5/0xe6 __kasan_report.cold+0x65/0x99 kasan_report+0x16/0x20 check_memory_region+0x140/0x1b0 memset+0x28/0x40 blk_mq_map_swqueue+0x775/0x810 blk_mq_update_nr_hw_queues+0x468/0x710 nullb_device_submit_queues_store+0xf7/0x1a0 [null_blk] configfs_write_file+0x1c4/0x250 [configfs] __vfs_write+0x4c/0x90 vfs_write+0x145/0x2c0 ksys_write+0xd7/0x180 __x64_sys_write+0x47/0x50 do_syscall_64+0x6f/0x2f0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reviewed-by: Ming Lei Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Johannes Thumshirn Cc: Keith Busch Fixes: ac0d6b926e74 ("block: Reduce the amount of memory required per request queue") Signed-off-by: Bart Van Assche --- block/blk-mq.c | 1 - 1 file changed, 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 7f996e427733..948523fbfa7f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2824,7 +2824,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, memcpy(new_hctxs, hctxs, q->nr_hw_queues * sizeof(*hctxs)); q->queue_hw_ctx = new_hctxs; - q->nr_hw_queues = set->nr_hw_queues; kfree(hctxs); hctxs = new_hctxs; }