From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2EACFAD2C; Wed, 6 Aug 2025 00:58:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754441917; cv=none; b=mIS9LvX9UZ+x7yCexuXQbWwb9cqjx9/DAGSB3wFKlAsey0xp2CVxk7PvUeev1kzp9UDEOI66poxlz/TfHtP6m5ELCvYayz8Zx6xbOVYxh01pErNaQvYaDHJiLdMbNVVvvnNyp6JqKFvP3sqxUwHMNUPm7dSfdQF8dFeEwAnxfyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754441917; c=relaxed/simple; bh=YV3P0WrF2xxL6MMhSPAdxp5AVr3TClpAXVq0Kl3GCJo=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=eSJ7MYP/xwLXiJxdpMPJlOVqOOGs0awWdt38fc9XOT7yC9s1SKtJV8Fqe42nEWQw9RH9suHk5jzxRBcK76ADU1OCx2PMe8hUlpJq49rhXZ3kPIzKkW4YnFrLsusyYqzHKp2jooW0YqeUiAafkWZgKNvjWyP0wBiBddCIV4cBFu0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4bxX3Q4ZJpzYQv79; Wed, 6 Aug 2025 08:58:26 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 490C81A0A27; Wed, 6 Aug 2025 08:58:25 +0800 (CST) Received: from [10.174.179.143] (unknown [10.174.179.143]) by APP4 (Coremail) with SMTP id gCh0CgA3sxOtqJJoRnLcCg--.39504S3; Wed, 06 Aug 2025 08:58:23 +0800 (CST) Subject: Re: [PATCH] block: prevent deadlock in del_gendisk() To: Hillf Danton , Yu Kuai Cc: Ujwal Kundur , axboe@kernel.dk, ming.lei@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+2e9e529ac0b319316453@syzkaller.appspotmail.com, "yukuai (C)" References: <20250803134114.2707-1-ujwal.kundur@gmail.com> <20250805120001.3990-1-hdanton@sina.com> From: Yu Kuai Message-ID: <8f1183d0-dfee-9448-446e-2a8846987319@huaweicloud.com> Date: Wed, 6 Aug 2025 08:58:21 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250805120001.3990-1-hdanton@sina.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgA3sxOtqJJoRnLcCg--.39504S3 X-Coremail-Antispam: 1UD129KBjvdXoW7GFy8Zw18KF4kCrWfXw4xWFg_yoW3urXE9a 4xCay8Jr15tw4SkF4YqF93Grn2kF1rAF48WF4rAFZ5uwnxZas8Jan8CrWruwsagF48J34v yr13C342gr4agjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbV8FF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_ Gr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IY64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7Mxk0xIA0c2IEe2xFo4CEbIxv r21lc7CjxVAaw2AFwI0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr 0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY 17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcV C0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY 6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvj DU0xZFpf9x0JUd-B_UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ 在 2025/08/05 19:59, Hillf Danton 写道: > On Mon, 4 Aug 2025 15:51:48 +0800 Yu Kuai wrote: >> �� 2025/08/03 21:41, Ujwal Kundur д��: >>> A potential unsafe locking scenario presents itself when >>> mutex_lock(&disk->open_mutex) is called with reader's lock held on >>> update_nr_hwq_lock: >>> CPU0 CPU1 >>> ---- ---- >>> rlock(&set->update_nr_hwq_lock) >>> lock(&nbd->config_lock); >>> lock(&set->update_nr_hwq_lock); >>> lock(&disk->open_mutex) >>> >> This problem is already fixed inside nbd by: >> 8b428f42f3ed ("nbd: fix lockdep deadlock warning") >> > Deadlock still exists [1]. > This deadlock is a different problem, not what you claimed to fix in this patch. Thanks, Kuai > [1] https://lore.kernel.org/lkml/6891742c.050a0220.7f033.001a.GAE@google.com/ > . >