From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sg-1-12.ptr.blmpb.com (sg-1-12.ptr.blmpb.com [118.26.132.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 170231D6193 for ; Tue, 10 Feb 2026 07:03:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=118.26.132.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770707025; cv=none; b=rByWa0OipDkHVujyBZ5+k6Xcx0UQRzJVRlh0RX1AXXSCYTicfVXzgYxCRjyYGinC0050rQ7uzxBbAZZeNMGN4Ij/EmdHnSrBzisMoDaEiEBpyQbcoar50popxWr6veWXX4BXwpN6P1wBQK8XsEXUHJhq7vrthCqUr8j1Y/4ciog= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770707025; c=relaxed/simple; bh=EjD+pRaHTolG3P0dFiBqPrhrRtG+Zz+PQwJlGziWUZ8=; h=Message-Id:References:Date:To:Content-Type:Subject:Mime-Version: In-Reply-To:From:Cc; b=JbZmlDIBVikW+iGbP6cM6+0geIVD86LFnMhV5JqWrzeAArVA4YO0OQPHRtkmB5B/w3GO5aanKzfrlquOG/9087Yu61jfffkkdEX92EFIn6lJBgwMyV80tcubvX1cDQCnL7gzRWbMl3eEV67beSRF+Tnkr0Aezz40UjPBRPgxzzQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com; spf=pass smtp.mailfrom=fnnas.com; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b=ozVs0UXO; arc=none smtp.client-ip=118.26.132.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fnnas.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b="ozVs0UXO" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=fnnas-com.20200927.dkim.feishu.cn; t=1770706777; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=EjD+pRaHTolG3P0dFiBqPrhrRtG+Zz+PQwJlGziWUZ8=; b=ozVs0UXOFBlEeE2cBk9Rw2e5fJAokY5WmKHFGqvTR2oGGrenp8IRHeek84EpSLAjuSJl7i FwZneB+jhpJQvl+5seJnAL8je83y2+pbb36AkWFYEZXkhAcv7lDwOZ8ypoorrlka6h8nlK d6NBY7lRD7KNlLplpzXTQC+H4TSGhk4nkWG48y6mpREx6RDHTbMPWAKgWsN/f9Lyt6SbQ0 GKWtA3YUgPfTcPVp2pQ3XgmWt/zfRQtwfbYgVisYCmDFo/0/arFz0cD6lyyPdeJ3cTA7IL 9EOCBzmL/KkLN0b5N6LZC328TcPIgQdngzM68hFiN4kl6zeHLp+JA1m99JNdzw== Message-Id: X-Original-From: Yu Kuai References: <20260209082953.3053721-1-yukuai@fnnas.com> <20260209082953.3053721-5-yukuai@fnnas.com> <6b18e0bc-efa7-4bd5-b12b-a313941d2ba1@acm.org> Content-Language: en-US User-Agent: Mozilla Thunderbird Date: Tue, 10 Feb 2026 14:59:32 +0800 To: "Bart Van Assche" , "Keith Busch" Content-Type: text/plain; charset=UTF-8 Reply-To: yukuai@fnnas.com Subject: Re: [PATCH 4/4] blk-mq: use blk_queue_enter/exit to protect debugfs file creation Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: From: "Yu Kuai" Received: from [192.168.1.104] ([39.182.0.137]) by smtp.feishu.cn with ESMTPS; Tue, 10 Feb 2026 14:59:34 +0800 X-Lms-Return-Path: Cc: , , , , , , , , , , , , , Hi, =E5=9C=A8 2026/2/10 1:51, Bart Van Assche =E5=86=99=E9=81=93: > On 2/9/26 9:33 AM, Keith Busch wrote: >> I had to look up the original commit that introduced the WARN, >> 65d466b629847. The commit message says "Creating new debugfs entries can >> trigger fs reclaim", so that must be the path that enters back into the >> block layer request_queue. > > Thanks Keith. It's probably a good idea to integrate this information in > the source code comment above the blk_queue_enter() call. Yeah, I'll add the information in the next version. BTW, I'd like to add something. The original lockdep report is: [REPORT] Possible circular locking dependency on 6.18-rc2 in=20 blkg_conf_open_bdev_frozen+0x80/0xa0 - David Wei And we see there some contexts like wbt/nbd can freeze queue fist and then = create debugfs entries, and it's fixed by the thread: [PATCH v9 0/8] blk-mq: fix possible deadlocks - Yu Kuai And the warning is added in this thread. > > Bart. --=20 Thansk, Kuai