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=-8.4 required=3.0 tests=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, USER_AGENT_SANE_1 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 85D85C2D0B1 for ; Tue, 4 Feb 2020 08:52:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 575AF2087E for ; Tue, 4 Feb 2020 08:52:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RuAABrbQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726684AbgBDIwg (ORCPT ); Tue, 4 Feb 2020 03:52:36 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:20448 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726053AbgBDIwg (ORCPT ); Tue, 4 Feb 2020 03:52:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580806354; 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=YDDftAtPJN7YLmiKkApk/wNe+ULS/HSMN+9U0StbKz4=; b=RuAABrbQZIo0i6eNctSfXSahbKX6zZbXfopqnw5rehnvPkxUVZvaZlM90l7Dho3BU3aRZm XEM9nP+9/2GWKZqhbNpqy4Fdi+hCSs8oaptjzBHHKHzB3wMhtXrvAHIWumyqxdyQaV+7Fg EWcnPKOKB/9wcy/AUZymiX3diUV+ii0= 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-224-NJboiqNtOkaW0opL38iU4A-1; Tue, 04 Feb 2020 03:52:31 -0500 X-MC-Unique: NJboiqNtOkaW0opL38iU4A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7C79E13E6; Tue, 4 Feb 2020 08:52:29 +0000 (UTC) Received: from ming.t460p (ovpn-8-32.pek2.redhat.com [10.72.8.32]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 108B989F01; Tue, 4 Feb 2020 08:52:22 +0000 (UTC) Date: Tue, 4 Feb 2020 16:52:18 +0800 From: Ming Lei To: Zhiqiang Liu Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Mingfangsen , "wubo (T)" , Guiyao , Yanxiaodan Subject: Re: [PATCH V5] brd: check and limit max_part par Message-ID: <20200204085218.GA19922@ming.t460p> References: <3f053491-d8c1-7092-58d1-85afaa2e68df@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3f053491-d8c1-7092-58d1-85afaa2e68df@huawei.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Feb 04, 2020 at 10:44:18AM +0800, Zhiqiang Liu wrote: > > In brd_init func, rd_nr num of brd_device are firstly allocated > and add in brd_devices, then brd_devices are traversed to add each > brd_device by calling add_disk func. When allocating brd_device, > the disk->first_minor is set to i * max_part, if rd_nr * max_part > is larger than MINORMASK, two different brd_device may have the same > devt, then only one of them can be successfully added. > when rmmod brd.ko, it will cause oops when calling brd_exit. > > Follow those steps: > # modprobe brd rd_nr=3 rd_size=102400 max_part=1048576 > # rmmod brd > then, the oops will appear. > > Oops log: > [ 726.613722] Call trace: > [ 726.614175] kernfs_find_ns+0x24/0x130 > [ 726.614852] kernfs_find_and_get_ns+0x44/0x68 > [ 726.615749] sysfs_remove_group+0x38/0xb0 > [ 726.616520] blk_trace_remove_sysfs+0x1c/0x28 > [ 726.617320] blk_unregister_queue+0x98/0x100 > [ 726.618105] del_gendisk+0x144/0x2b8 > [ 726.618759] brd_exit+0x68/0x560 [brd] > [ 726.619501] __arm64_sys_delete_module+0x19c/0x2a0 > [ 726.620384] el0_svc_common+0x78/0x130 > [ 726.621057] el0_svc_handler+0x38/0x78 > [ 726.621738] el0_svc+0x8/0xc > [ 726.622259] Code: aa0203f6 aa0103f7 aa1e03e0 d503201f (7940e260) > > Here, we add brd_check_and_reset_par func to check and limit max_part par. > > -- > V4->V5:(suggested by Ming Lei) > - make sure max_part is not larger than DISK_MAX_PARTS > > V3->V4:(suggested by Ming Lei) > - remove useless change > - add one limit of max_part > > V2->V3: (suggested by Ming Lei) > - clear .minors when running out of consecutive minor space in brd_alloc > - remove limit of rd_nr > > V1->V2: > - add more checks in brd_check_par_valid as suggested by Ming Lei. > > Signed-off-by: Zhiqiang Liu > Reviewed-by: Bob Liu > --- > drivers/block/brd.c | 27 +++++++++++++++++++++++---- > 1 file changed, 23 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/brd.c b/drivers/block/brd.c > index df8103dd40ac..6b9db3f63cb7 100644 > --- a/drivers/block/brd.c > +++ b/drivers/block/brd.c > @@ -389,11 +389,12 @@ static struct brd_device *brd_alloc(int i) > * is harmless) > */ > blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE); > - disk = brd->brd_disk = alloc_disk(max_part); > + disk = brd->brd_disk = alloc_disk(((i * max_part) & ~MINORMASK) ? > + 0 : max_part); > if (!disk) > goto out_free_queue; > disk->major = RAMDISK_MAJOR; > - disk->first_minor = i * max_part; > + disk->first_minor = i * disk->minors; As I told you, the above change isn't needed, otherwise: Reviewed-by: Ming Lei Thanks, Ming