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=-10.1 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,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 AA0FAC433DF for ; Wed, 5 Aug 2020 03:35:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8666B2177B for ; Wed, 5 Aug 2020 03:35:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JPe9ar/t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726104AbgHEDfy (ORCPT ); Tue, 4 Aug 2020 23:35:54 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:54710 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725981AbgHEDfy (ORCPT ); Tue, 4 Aug 2020 23:35:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596598552; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YQcOfU+ObUoQVxma4hHVDgnY6H72EmxRxUeQAM8SZuI=; b=JPe9ar/tJQUCqA1olyhMNRFZgzwWcmmXk38rxhSHOYQVRerVGWGgZ+a6g+WXLmuqnvGYxP 0tjpginQhE8LIE+a9LgnkbvqgiatpzC8n+kbup8xuZ6PKZTcnHMpO/Zo4wi9MVgvlixIn6 zA8SVQJs2ElB3zsnNwlY5szaG5Em3sg= 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-189-4_dS3A8SNdGrkPCbG-uFMA-1; Tue, 04 Aug 2020 23:34:44 -0400 X-MC-Unique: 4_dS3A8SNdGrkPCbG-uFMA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2F9B28064DE; Wed, 5 Aug 2020 03:34:43 +0000 (UTC) Received: from T590 (ovpn-13-169.pek2.redhat.com [10.72.13.169]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 992CD5F21A; Wed, 5 Aug 2020 03:34:33 +0000 (UTC) Date: Wed, 5 Aug 2020 11:34:28 +0800 From: Ming Lei To: Coly Li Cc: linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, Bart Van Assche , Christoph Hellwig , Enzo Matsumiya , Evan Green , Hannes Reinecke , Jens Axboe , "Martin K . Petersen" , Xiao Ni Subject: Re: [PATCH v2] block: check queue's limits.discard_granularity in __blkdev_issue_discard() Message-ID: <20200805033428.GB1986549@T590> References: <20200805025723.37726-1-colyli@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200805025723.37726-1-colyli@suse.de> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-bcache-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On Wed, Aug 05, 2020 at 10:57:23AM +0800, Coly Li wrote: > If create a loop device with a backing NVMe SSD, current loop device > driver doesn't correctly set its queue's limits.discard_granularity and > leaves it as 0. If a discard request at LBA 0 on this loop device, in > __blkdev_issue_discard() the calculated req_sects will be 0, and a zero > length discard request will trigger a BUG() panic in generic block layer > code at block/blk-mq.c:563. > > [ 955.565006][ C39] ------------[ cut here ]------------ > [ 955.559660][ C39] invalid opcode: 0000 [#1] SMP NOPTI > [ 955.622171][ C39] CPU: 39 PID: 248 Comm: ksoftirqd/39 Tainted: G E 5.8.0-default+ #40 > [ 955.622171][ C39] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE160M-2.70]- 07/17/2020 > [ 955.622175][ C39] RIP: 0010:blk_mq_end_request+0x107/0x110 > [ 955.622177][ C39] Code: 48 8b 03 e9 59 ff ff ff 48 89 df 5b 5d 41 5c e9 9f ed ff ff 48 8b 35 98 3c f4 00 48 83 c7 10 48 83 c6 19 e8 cb 56 c9 ff eb cb <0f> 0b 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 56 41 54 > [ 955.622179][ C39] RSP: 0018:ffffb1288701fe28 EFLAGS: 00010202 > [ 955.749277][ C39] RAX: 0000000000000001 RBX: ffff956fffba5080 RCX: 0000000000004003 > [ 955.749278][ C39] RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000 > [ 955.749279][ C39] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > [ 955.749279][ C39] R10: ffffb1288701fd28 R11: 0000000000000001 R12: ffffffffa8e05160 > [ 955.749280][ C39] R13: 0000000000000004 R14: 0000000000000004 R15: ffffffffa7ad3a1e > [ 955.749281][ C39] FS: 0000000000000000(0000) GS:ffff95bfbda00000(0000) knlGS:0000000000000000 > [ 955.749282][ C39] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 955.749282][ C39] CR2: 00007f6f0ef766a8 CR3: 0000005a37012002 CR4: 00000000007606e0 > [ 955.749283][ C39] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 955.749284][ C39] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 955.749284][ C39] PKRU: 55555554 > [ 955.749285][ C39] Call Trace: > [ 955.749290][ C39] blk_done_softirq+0x99/0xc0 > [ 957.550669][ C39] __do_softirq+0xd3/0x45f > [ 957.550677][ C39] ? smpboot_thread_fn+0x2f/0x1e0 > [ 957.550679][ C39] ? smpboot_thread_fn+0x74/0x1e0 > [ 957.550680][ C39] ? smpboot_thread_fn+0x14e/0x1e0 > [ 957.550684][ C39] run_ksoftirqd+0x30/0x60 > [ 957.550687][ C39] smpboot_thread_fn+0x149/0x1e0 > [ 957.886225][ C39] ? sort_range+0x20/0x20 > [ 957.886226][ C39] kthread+0x137/0x160 > [ 957.886228][ C39] ? kthread_park+0x90/0x90 > [ 957.886231][ C39] ret_from_fork+0x22/0x30 > [ 959.117120][ C39] ---[ end trace 3dacdac97e2ed164 ]--- > > This is the procedure to reproduce the panic, > # modprobe scsi_debug delay=0 dev_size_mb=2048 max_queue=1 > # losetup -f /dev/nvme0n1 --direct-io=on > # blkdiscard /dev/loop0 -o 0 -l 0x200 > > This patch fixes the issue by checking q->limits.discard_granularity in > __blkdev_issue_discard() before composing the discard bio. If the value > is 0, then prints a warning oops information and returns -EOPNOTSUPP to > the caller to indicate that this buggy device driver doesn't support > discard request. > > Fixes: 9b15d109a6b2 ("block: improve discard bio alignment in __blkdev_issue_discard()") > Fixes: c52abf563049 ("loop: Better discard support for block devices") > Reported-and-suggested-by: Ming Lei > Signed-off-by: Coly Li > Cc: Bart Van Assche > Cc: Christoph Hellwig > Cc: Enzo Matsumiya > Cc: Evan Green > Cc: Hannes Reinecke > Cc: Jens Axboe > Cc: Martin K. Petersen > Cc: Ming Lei > Cc: Xiao Ni > --- > Changelog: > v2: fix typo of the wrong return error code. > v1: first version. > > block/blk-lib.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/block/blk-lib.c b/block/blk-lib.c > index 019e09bb9c0e..729f05729529 100644 > --- a/block/blk-lib.c > +++ b/block/blk-lib.c > @@ -47,6 +47,10 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, > op = REQ_OP_DISCARD; > } > > + /* In case the discard granularity isn't set by buggy device driver */ > + if (WARN_ON_ONCE(!q->limits.discard_granularity)) > + return -EOPNOTSUPP; > + > bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; > if ((sector | nr_sects) & bs_mask) > return -EINVAL; > -- > 2.26.2 > Looks fine: Reviewed-by: Ming Lei BTW, it might be helpful to print the buggy disk name, so that people can find the related driver easily. Thanks, Ming