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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B89E8C52D5C for ; Thu, 27 Feb 2020 13:59:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CDE32073D for ; Thu, 27 Feb 2020 13:59:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811950; bh=sXKr07LhSMJaxeyVmTeEL6LuRaf6FLMgJOtCXcSEip8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NUPfjpdUJhsJrcfK59FSCT31xhm8v2jIxNU7wolKW02KSV2Bt1gmL1Gbh4R54KB+o 5+TbAEdciFvkaNYgdDhFWhBI3L01tPTntvXaH/FLkdV9kxFlQS3vmbo2E++gbV7AnJ 3j878dFHmtlSxo1hFpnFFVxYu07QPiwawV2JC6pw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732579AbgB0N7J (ORCPT ); Thu, 27 Feb 2020 08:59:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:60386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732557AbgB0N7D (ORCPT ); Thu, 27 Feb 2020 08:59:03 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A47E124691; Thu, 27 Feb 2020 13:59:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811943; bh=sXKr07LhSMJaxeyVmTeEL6LuRaf6FLMgJOtCXcSEip8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mPJtU7II1kCVgDB5iO787NeU2lz0nXiZrXEWIxNTU5JNSLaz81yROV4esKVq5laxe Rqthil7E6VVDeVcB+6+Z1BIXc59akrywuw2k4X/7L7J8iEUVJ7OGTVOGyHp+28+R1w uH4SQa7MoiypGmFUDWH793BZPkavkvMIgx+J07FY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhiqiang Liu , Bob Liu , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 4.14 162/237] brd: check and limit max_part par Date: Thu, 27 Feb 2020 14:36:16 +0100 Message-Id: <20200227132308.417513087@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhiqiang Liu [ Upstream commit c8ab422553c81a0eb070329c63725df1cd1425bc ] 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. -- V5->V6: - remove useless code 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 Reviewed-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/brd.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 2d7178f7754ed..0129b1921cb36 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -529,6 +529,25 @@ static struct kobject *brd_probe(dev_t dev, int *part, void *data) return kobj; } +static inline void brd_check_and_reset_par(void) +{ + if (unlikely(!max_part)) + max_part = 1; + + /* + * make sure 'max_part' can be divided exactly by (1U << MINORBITS), + * otherwise, it is possiable to get same dev_t when adding partitions. + */ + if ((1U << MINORBITS) % max_part != 0) + max_part = 1UL << fls(max_part); + + if (max_part > DISK_MAX_PARTS) { + pr_info("brd: max_part can't be larger than %d, reset max_part = %d.\n", + DISK_MAX_PARTS, DISK_MAX_PARTS); + max_part = DISK_MAX_PARTS; + } +} + static int __init brd_init(void) { struct brd_device *brd, *next; @@ -552,8 +571,7 @@ static int __init brd_init(void) if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) return -EIO; - if (unlikely(!max_part)) - max_part = 1; + brd_check_and_reset_par(); for (i = 0; i < rd_nr; i++) { brd = brd_alloc(i); -- 2.20.1