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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BF93C433FE for ; Sat, 12 Nov 2022 10:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234321AbiKLK5P (ORCPT ); Sat, 12 Nov 2022 05:57:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230170AbiKLK5N (ORCPT ); Sat, 12 Nov 2022 05:57:13 -0500 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A88D1B867; Sat, 12 Nov 2022 02:57:11 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4N8XZn6nY5z4f3jZ3; Sat, 12 Nov 2022 18:57:05 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP4 (Coremail) with SMTP id gCh0CgC329gDfG9jUJSaAQ--.9600S3; Sat, 12 Nov 2022 18:57:09 +0800 (CST) Subject: Re: [PATCH] blk-mq: only unregister sysfs when registration succeeded To: Yu Kuai , Liu Shixin , Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, "yukuai (C)" References: <20221112110754.1109979-1-liushixin2@huawei.com> <607beb5b-8d54-b795-8a05-76352d7ed863@huaweicloud.com> From: Yu Kuai Message-ID: <58ab3673-3e39-9ea9-1749-eebfcfb8a10f@huaweicloud.com> Date: Sat, 12 Nov 2022 18:57:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <607beb5b-8d54-b795-8a05-76352d7ed863@huaweicloud.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: gCh0CgC329gDfG9jUJSaAQ--.9600S3 X-Coremail-Antispam: 1UD129KBjvdXoWrury7Xr4kCr4UXw47Kry7trb_yoW3ArgEga y8KFWkWa1DGFnxKw12kFZrZFyxZ3WvgFyfJayDJFWDtw18WaykGr4j9r17CrWUKw4xCrn8 trW0gayfGrWagjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb4AFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j 6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCYjI0SjxkI62AI1cAE67vI Y487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV W8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Wr1j6rW3Jr1lIxAIcVC2z280aVAFwI0_Jr0_ Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VU1a9aP UUUUU== X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2022/11/12 18:44, Yu Kuai дµÀ: > Hi, > > ÔÚ 2022/11/12 19:07, Liu Shixin дµÀ: >> kobject_del() must not be called if kobject_add() has not been called. >> Hence only unregister sysfs when registration succeeded. >> > > From what I see, the blk_queue_registered() from caller > blk_unregister_queue() can already prevent that. QUEUE_FLAG_REGISTERED > will only be set if blk_register_queue() succeed. I see that the return value of blk_mq_sysfs_register() is not checked from blk_register_queue(), there will be memleak or uaf from error path. Hence I think better thing to do is to handle the case that blk_mq_sysfs_register() faild, and clean up if blk_mq_sysfs_register() succeed while follow up procedures failed from blk_register_queue().