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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 734DDC11D24 for ; Fri, 21 Feb 2020 03:22:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5228B24654 for ; Fri, 21 Feb 2020 03:22:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729595AbgBUDW6 (ORCPT ); Thu, 20 Feb 2020 22:22:58 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:33274 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729280AbgBUDW6 (ORCPT ); Thu, 20 Feb 2020 22:22:58 -0500 Received: by mail-pg1-f193.google.com with SMTP id 6so292415pgk.0 for ; Thu, 20 Feb 2020 19:22:58 -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=vJCLdqILp21uMrXCuSy7CxSeezDCusWqSkTR2T0a8u4=; b=AybcCkoo6d9tkCBo+g3wzN1viKL3LcO8QfKF9nmYdeA9QXP19TTHeAcwH7WMKIHHZd 1HuNzWkOJhSGVXUSlvefKmXqt6Ww5QOCoEutu+mvIKyKPqPYvOeoVt1j9Q/w7xG1b5UJ ZrpDm5LRqGog8WGVSpjKOjI69S4LxQR06gXqwy/rrEH4EiZIn/LBJO/33A8v4/VsB0DY JhPcKMDZKbXPbOGdRyUHBMwHfgAiWpVghy6Clf5Exgp4qrKIyPUwYqwqcU3od6VHKfvQ uyrKj71a/S4b0VbbrJAC0lT4mywD3N2km1TSaHrHFwXsz5fhX+A+jCEcjcmoSVnjJ+ll YHGQ== X-Gm-Message-State: APjAAAXAoNfAf/wG2DmpsiexgEsVQI5RmuXMCRwWKQwFir1ar+J5vqkF J66Z9dazss6kkmmNEylDvBk= X-Google-Smtp-Source: APXvYqyt1qE5WymJzmSDtLLLBVWcQ36bqsbOqWjRh/sm8A9keisUV0e9nAofkpjcHS2MPM4LtcWNxQ== X-Received: by 2002:a63:78c7:: with SMTP id t190mr38039402pgc.416.1582255377749; Thu, 20 Feb 2020 19:22:57 -0800 (PST) Received: from asus.hsd1.ca.comcast.net ([2601:647:4000:d7:e57a:a1b3:1a44:bb8c]) by smtp.gmail.com with ESMTPSA id x197sm1010517pfc.1.2020.02.20.19.22.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 19:22:57 -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 v3 3/8] blk-mq: Fix a recently introduced regression in blk_mq_realloc_hw_ctxs() Date: Thu, 20 Feb 2020 19:22:38 -0800 Message-Id: <20200221032243.9708-4-bvanassche@acm.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200221032243.9708-1-bvanassche@acm.org> References: <20200221032243.9708-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 a92444c077bc..49fa56fc48de 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; }