From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 004.mia.mailroute.net (004.mia.mailroute.net [199.89.3.7]) (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 D42BE21FF25; Mon, 7 Jul 2025 17:39:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.3.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751909998; cv=none; b=tQ+/AlSYWTA2Ue3KDAjPQoZhz+pWZp0Jufv3bVwCB6D+O9ZZQwcQKp4Ctwe5SH0pjsFu79J5s8fDpOQFc0MLnnd3xP+skx9jiye9LtlgYjh8tuXQRGTkx8lifhctTQWPu5Et6mz/a5x+rXxjrcOxe0xjFEx6ecW05zUqsmqGpDE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751909998; c=relaxed/simple; bh=XmTOTUwfpQebFQ3AejzO16POnbpNVtdewYMRmEHOYVQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=c5ZzfVdrnRECSk03EThgTXYFuNK0ltd6er8ceuBsMNNJGHR9H5uPmTs/h5mpOKrsALFNC106qJWn5ldaepvVUcdVChizi9Cerpjz/1trUnsO/InjSYdlbVr3EITKJwBqjbYLjfjTX8JmlK9DWvZFUekBmhsDaj5W4oQlsadzvpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=XRufL2tJ; arc=none smtp.client-ip=199.89.3.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="XRufL2tJ" Received: from localhost (localhost [127.0.0.1]) by 004.mia.mailroute.net (Postfix) with ESMTP id 4bbWhq5bKDzm0ySG; Mon, 7 Jul 2025 17:39:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1751909993; x=1754501994; bh=jo1ezI3yg8pDe+rN9VdHGNjY QJTmcSIi+8PfDwfiijE=; b=XRufL2tJdVxjU2RRAyaT2I38aGt8E1OjOCkP4dN7 AXalL2QIKRBBI774gtJ0hNpeTOpO1oZQN4Q353+PE0Lp/lWrtOpwPYhHYkWO1Uie X9qRaF2dhUURQA63yUPzlazquMBmDILjywVquRYqngRouSvAWm+wCOpRgLHdzJB/ joq7VJEZwxc4lAaZceTaOHWB9hYf0936iHdnYcl3RDnw7kxQ+VoPMdXOMO63Nnmk ZjLsyJG4qoaUSXiP/6JYpSmZaIM7wpnztlP9ICij2790239b/T4FqA7tgc0Q7IBA 5BoLTl2uewN8Bc3cUQ+3VB8h+8IiH1EK8+/NjX7VqQf1hg== X-Virus-Scanned: by MailRoute Received: from 004.mia.mailroute.net ([127.0.0.1]) by localhost (004.mia [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id j79FvH-RSEao; Mon, 7 Jul 2025 17:39:53 +0000 (UTC) Received: from [100.66.154.22] (unknown [104.135.204.82]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 004.mia.mailroute.net (Postfix) with ESMTPSA id 4bbWhf5Qptzm0yTF; Mon, 7 Jul 2025 17:39:45 +0000 (UTC) Message-ID: Date: Mon, 7 Jul 2025 10:39:44 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [nbd?] possible deadlock in nbd_queue_rq To: Hillf Danton , syzbot Cc: axboe@kernel.dk, josef@toxicpanda.com, linux-block@vger.kernel.org, Ming Lei , Tetsuo Handa , linux-kernel@vger.kernel.org, nbd@other.debian.org, syzkaller-bugs@googlegroups.com References: <20250707005946.2669-1-hdanton@sina.com> Content-Language: en-US From: Bart Van Assche In-Reply-To: <20250707005946.2669-1-hdanton@sina.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/6/25 5:59 PM, Hillf Danton wrote: > and given the second one, the report is false positive. Whether or not this report is a false positive, the root cause should be fixed because lockdep disables itself after the first circular locking complaint. From print_usage_bug() in kernel/locking/lockdep.c: if (!debug_locks_off() || debug_locks_silent) return; Bart.