From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 0E03813C82E for ; Thu, 3 Jul 2025 09:09:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751533751; cv=none; b=K9N8Z7r+aXiVsQlj637GqhcH+JAowO7kPZ9dMG5Es0XVd7PPYU8keg3TKSLZt9zJFcPMWDOAYWiXWWYLTjOBMEs3XLZ4Sy8ViT+2M716V4uypkM7qGvGEWB0rgVbcEr/73O9Gwj18tHIc892yhs9KOLhL/dkhyawWihQmHTP3Ns= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751533751; c=relaxed/simple; bh=L3OqQp+TqpqWebCRXu/q5UG3tlU0zH3uyyd0hyMA1lM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Oi6sKUzwnGkDiC5EWIhzuxZXR1yiSg0Uqv9TNSCtGH29CD/GM+hsEJ7CHDHZqDihLvOJham1fuOxIAc3Lj2fO/77eWtICHyp205yZmHcyyphztDzu1yn74d8I+I+Xk/e5ubOSPuHSPBa9dmJf+w/1g2QgKrTlKyTsfQK3Y1jR78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 7560E68B05; Thu, 3 Jul 2025 11:09:06 +0200 (CEST) Date: Thu, 3 Jul 2025 11:09:06 +0200 From: Christoph Hellwig To: Bart Van Assche Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH 0/3] Fix a deadlock related to modifying queue attributes Message-ID: <20250703090906.GG4757@lst.de> References: <20250702182430.3764163-1-bvanassche@acm.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250702182430.3764163-1-bvanassche@acm.org> User-Agent: Mutt/1.5.17 (2007-11-01) I'm still very doubtful on this whole approach, and I think you are ignoring the root cause, which is dm-multipath keeping a q_usage_count reference for an unbounded time. It is only supposed to be held over I/O, and I/O is expected to time out. You'll probably get much farther by changing dm-multipath to not hold a q_usage_count reference for something not actually under I/O.