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 D5805D132C0 for ; Mon, 4 Nov 2024 13:16:58 +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=9dQMIo4U+a5p71IonR9Lfh1NJeFSo+vQhuHuUkSOZEo=; b=YrEPGiQF0I5d0ofuKgo8P1nZJO t5+ZGs9giM3/0Fgv/YD0GQDjdnS7o/aUta5xi2Xc053R4UH1LVjlbjgYSDM7lpJGdtHzqQZ4RwpBZ lfXdleGT2I7au+JyvcynS2b6gcBBU6jbCZvc9WAIlbhHMDnwLGWvvyIxHwQRDcOtphnY3ypC85Qza BY+nFjUr0V7DqpimF0v1Es5L/POKx0+t9KKi/ugp6iOYS3uBnAbKWviDGlupbgCr0E/1UbLzYmWKi ib4lv9+nlclolM7k2K6JmeFggtDWJeslNzEMbaCZj20dIRHj1261bvtdYltUHD6IeKgBQ2a/1VDTz QZOaxP3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t7wwz-0000000DoRk-1BbK; Mon, 04 Nov 2024 13:16:57 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t7www-0000000DoQs-3VLc for linux-nvme@lists.infradead.org; Mon, 04 Nov 2024 13:16:56 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 39374227AAF; Mon, 4 Nov 2024 14:16:52 +0100 (CET) Date: Mon, 4 Nov 2024 14:16:52 +0100 From: Christoph Hellwig To: Breno Leitao Cc: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] nvme/host: Fix RCU list traversal to use SRCU primitive Message-ID: <20241104131652.GB14373@lst.de> References: <20241104-nvme_rcu-v1-1-ecb19f5c95fa@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241104-nvme_rcu-v1-1-ecb19f5c95fa@debian.org> 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-20241104_051655_043701_8F8C7EF8 X-CRM114-Status: GOOD ( 17.53 ) 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 04, 2024 at 04:24:40AM -0800, Breno Leitao wrote: > The code currently uses list_for_each_entry_rcu() while holding an SRCU > lock, triggering false positive warnings with CONFIG_PROVE_RCU=y > enabled: > > drivers/nvme/host/core.c:3770 RCU-list traversed in non-reader section!! > > While the list is properly protected by SRCU lock, the code uses the wrong > list traversal primitive. Replace list_for_each_entry_rcu() with > list_for_each_entry_srcu() to correctly indicate SRCU-based protection > and eliminate the false warning. I didn't even know there was such as thing as list_for_each_entry_srcu, but apparently it's been there for a while. Looks good: Reviewed-by: Christoph Hellwig > Something similar will need to be done for multipath. I will get it done > once I get some feedback about this patch first. Thanks!