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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2CEE0C3B1A6 for ; Fri, 14 Feb 2020 17:17:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05B58206CC for ; Fri, 14 Feb 2020 17:17:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581700651; bh=o2SSratsKeLW5BDF4DIAFp+zHraaHnFQYUKoplhPdFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bk8cUci3CBYzPQQI3I4E0trBwM8TgyVRw/U/gysopNBFtu7DYWoqQb83kUsa2pdDE AqP4YJZbhVsJ0hftOFiFIH4i0hruPaC0PdAcCjMBGiMfMlj6iSp9TvgMa/iwZy6khM +/M5GHgYP9yD6AjhIn5yMgbypdDnwesWQ0W3T7OQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391766AbgBNQLW (ORCPT ); Fri, 14 Feb 2020 11:11:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:37964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391487AbgBNQLV (ORCPT ); Fri, 14 Feb 2020 11:11:21 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5BB472469D; Fri, 14 Feb 2020 16:11:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696680; bh=o2SSratsKeLW5BDF4DIAFp+zHraaHnFQYUKoplhPdFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z8RK7YIi0yx2u/QI4L1BAqBrzvpjAlfvVbKdhv4MC4VfAR/0MIe7fKKULHj28kGMH JhPIq8MpGUATlftBYtBLFTmwUbZq98Nwds/JpFR75oJXt9GxcyM2HGhHY0iDMPEnmz 8xdnOpKD07pQNOuUKd/SV5/nFrPTyiHYTO1g6YJw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhiqiang Liu , Bob Liu , Ming Lei , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 448/459] brd: check and limit max_part par Date: Fri, 14 Feb 2020 11:01:38 -0500 Message-Id: <20200214160149.11681-448-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@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 c548a5a6c1a00..79f18cfa7049f 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -470,6 +470,25 @@ 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; @@ -493,8 +512,7 @@ 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