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 1C519C00140 for ; Mon, 1 Aug 2022 01:04:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231234AbiHABEr (ORCPT ); Sun, 31 Jul 2022 21:04:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238616AbiHABEq (ORCPT ); Sun, 31 Jul 2022 21:04:46 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC82D11472 for ; Sun, 31 Jul 2022 18:04:44 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Lx0HN0NdHzKGpk for ; Mon, 1 Aug 2022 09:03:28 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP3 (Coremail) with SMTP id _Ch0CgA3tzCoJudi5cI3AA--.46416S3; Mon, 01 Aug 2022 09:04:41 +0800 (CST) Subject: Re: [PATCH 7/8] dm: delay registering the gendisk To: Yu Kuai , Christoph Hellwig Cc: Jens Axboe , Mike Snitzer , dm-devel@redhat.com, linux-block@vger.kernel.org, "yukuai (C)" , "zhangyi (F)" References: <20210804094147.459763-1-hch@lst.de> <20210804094147.459763-8-hch@lst.de> <20220707052425.GA13016@lst.de> <6ff5c130-b5b1-b611-bb99-6a2275404fcd@huaweicloud.com> From: Yu Kuai Message-ID: Date: Mon, 1 Aug 2022 09:04:40 +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: <6ff5c130-b5b1-b611-bb99-6a2275404fcd@huaweicloud.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: _Ch0CgA3tzCoJudi5cI3AA--.46416S3 X-Coremail-Antispam: 1UD129KBjvJXoW7tFy3ZF17tw4fAF1kKF1DGFg_yoW8AFWfpa 48JFs0krZrXrs7W397t34UZr9Yvr4UJw1UJry5GFyxKryDWr9Yqr4xXF4qgFy7Jr4kWr1j qF4Utry5Zr4kA37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkE14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7I2V7IY0VAS07AlzVAY IcxG8wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE14v26r1j 6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUZa9 -UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi, Christoph! 在 2022/07/15 11:24, Yu Kuai 写道: > Hi, Christoph! > > 在 2022/07/07 15:20, Yu Kuai 写道: >> 在 2022/07/07 13:24, Christoph Hellwig 写道: >>> On Thu, Jul 07, 2022 at 11:29:26AM +0800, Yu Kuai wrote: >>>> We found that this patch fix a nullptr crash in our test: >>> >>>> Do you think it's ok to backport this patch(and all realted patches) to >>>> lts, or it's better to fix that bio can be submitted with queue >>>> uninitialized from block layer? >>> >>> Given how long ago this was I do not remember offhand how much prep >>> work this would require.  The patch itself is of course tiny and >>> backportable, but someone will need to do the work and figure out how >>> much else would have to be backported. >> >> Ok, I'll try to figure out that, and backport them.(At least to 5.10.y) I posted a stable patchset on stable 5.10, can you pleas take a loock ? dm: fix nullptr crash https://lore.kernel.org/all/20220729062356.1663513-1-yukuai1@huaweicloud.com/ Thanks, Kuai > > While reviewing the code, I didn't found any protection that > bd_link_disk_holder() won't concurrent with > bd_register_pending_holders(). If they do can concurrent, > following scenario is problematic: > > t1                t2 > device_add_disk >  disk->slave_dir = kobject_create_and_add >                 bd_link_disk_holder >                  __link_disk_holder >                  list_add >  bd_register_pending_holders >   list_for_each_entry >    __link_disk_holder -> -EEXIST > > In this case, I think maybe ignore '-EEXIST' is fine. > > I'm not familiar with dm, and I'm not sure if I missed something, > please kindly correct me if I'm wrong. > > Thanks, > Kuai > > . > 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 090DBC00140 for ; Mon, 1 Aug 2022 01:05:01 +0000 (UTC) DKIM-Signature: v=1; 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Mon, 1 Aug 2022 01:04:50 +0000 (UTC) Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-15-sKnw3CeNOK24FQ2gNPquKg-1; Sun, 31 Jul 2022 21:04:47 -0400 X-MC-Unique: sKnw3CeNOK24FQ2gNPquKg-1 Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Lx0HN0WKszKH4k; Mon, 1 Aug 2022 09:03:28 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP3 (Coremail) with SMTP id _Ch0CgA3tzCoJudi5cI3AA--.46416S3; Mon, 01 Aug 2022 09:04:41 +0800 (CST) To: Yu Kuai , Christoph Hellwig References: <20210804094147.459763-1-hch@lst.de> <20210804094147.459763-8-hch@lst.de> <20220707052425.GA13016@lst.de> <6ff5c130-b5b1-b611-bb99-6a2275404fcd@huaweicloud.com> From: Yu Kuai Message-ID: Date: Mon, 1 Aug 2022 09:04:40 +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: <6ff5c130-b5b1-b611-bb99-6a2275404fcd@huaweicloud.com> X-CM-TRANSID: _Ch0CgA3tzCoJudi5cI3AA--.46416S3 X-Coremail-Antispam: 1UD129KBjvJXoW7tFy3ZF17tw4fAF1kKF1DGFg_yoW8AFWfpa 48JFs0krZrXrs7W397t34UZr9Yvr4UJw1UJry5GFyxKryDWr9Yqr4xXF4qgFy7Jr4kWr1j qF4Utry5Zr4kA37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkE14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7I2V7IY0VAS07AlzVAY IcxG8wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE14v26r1j 6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUZa9 -UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; 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