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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 62792CCFA1A for ; Tue, 11 Nov 2025 07:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=11KRJ4oJxwIlBWAUpVSkTom0CFoXkC8tXdpoN+rIfmg=; b=OhIFOsN2yT8MoZdZJW0bscTG/o TNdf/3xdd3DrrD2HnkMDgc2bvcBeKpZng7oeeUK3n4TMYHW3AfKnJ/8Nshbx2Rm54j6Zu+dUVQd96 a212iZmaP47PQzz8Mz3SFWc212eXowwBYQxVRjMDCh8oXlx2z8neUz7i4kxKtwDcpNrdjWBd3B93V H7XA+3jWUgufdiupkcwF5fn/ssO4b6GK8myN3H7tk7aPpPZuWrUW+y8AEwdq+xxc0gug/EhVWwgGu Mtx5wiMocMJMFa60ENtQZmoKelSMzYAFv2XOcRyqxiktPPnTUBRQDT67dvv6763tZ1XxaUqskOt4/ gCnHfCrw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vIiab-00000006fS0-0xUD; Tue, 11 Nov 2025 07:14:53 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vIiaX-00000006fRP-2iAO for linux-nvme@lists.infradead.org; Tue, 11 Nov 2025 07:14:51 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id CF1FA227AA8; Tue, 11 Nov 2025 08:14:39 +0100 (CET) Date: Tue, 11 Nov 2025 08:14:39 +0100 From: Christoph Hellwig To: Keith Busch Cc: Matthew Wilcox , Keith Busch , hch@lst.de, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, axboe@kernel.dk Subject: Re: [PATCHv5 1/2] block: accumulate memory segment gaps per bio Message-ID: <20251111071439.GA4240@lst.de> References: <20251014150456.2219261-1-kbusch@meta.com> <20251014150456.2219261-2-kbusch@meta.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251110_231449_830628_47DF8271 X-CRM114-Status: GOOD ( 13.57 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Nov 10, 2025 at 11:50:51PM -0500, Keith Busch wrote: > Thanks for the heads up. This is in the path I'd been modifying lately, > so sounds plausible that I introduced the bug. The information here > should be enough for me to make progress: it looks like req->bio is NULL > in your trace, which I did not expect would happen. But it's late here > too, so look with fresh eyes in the morning. req->bio should only be NULL for flush requests or passthrough requests that do not transfer data. None of them should end up in this path.