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 8C478C44501 for ; Fri, 10 Jul 2026 12:58:02 +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=GJ+ZZjoXshQwp4HjCw3hwahYLU+lQJ/F/RXGt07TIgQ=; b=GEoos3RBlfpsYpxV3H7Qu3bGEN kPVkDnOBZVnzD5R9djB7LySNIeQlDkNImv3nwS3jDU4M3Sxl1Ib1O8vlwr7dCx3JUOGkoVUX5/dhY qvY9gSXybRC6t4mrEmpVI2VmGcYwA9n2GWWEMj7TuKMIeUGCsesf65mNLAaHaid5IsN6pkCJGYk+O iOplZ5wF8foed1WQ3rjkLk9lNkRYePoy2ukXj8lBnyUEgXOqSItCx6c+0SIEzv8dk4Ysi8aiugsIe UlYsw2y+JBSUwd5aprQeVKm+74b2gfMRcVSEvHL2G+9pldwAILCdKcPCV+2MGPQYriv8XtkH1OHl/ eHh12Byw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wiAnj-00000004xYl-3EU2; Fri, 10 Jul 2026 12:57:55 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wiAni-00000004xYZ-1XVh for linux-arm-kernel@lists.infradead.org; Fri, 10 Jul 2026 12:57:54 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 8BB2560052; Fri, 10 Jul 2026 12:57:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 400BA1F000E9; Fri, 10 Jul 2026 12:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783688273; bh=GJ+ZZjoXshQwp4HjCw3hwahYLU+lQJ/F/RXGt07TIgQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=LZynFH0m2Au0GulWeBOL9Se7/aaURATREjA+Ms9gJ6cf6EtMIjnSwTCzlx6N02XnT dmeQJC81rdCvri3euXeoAfSFGRC9CIcPElPxCiLeWREStZCOdOcBu/+qjU0yCmT0QP enmkG7dOtBv4nDyzVsVDneapP70gJ5rRL8UmcRvS6VjvhQn6RB008l2MD2l32xfGXG 5cYGi71NQAngfXSfymfzcPQ2MPJVVaecPUhTIsgTQH82cuEl6S9WmxjFwNuGAgHhNP P2e2TfAIlREWpipjFo8pinavN75nYQAV2KudNOomqBE4nuw3/+drShM6jwi7qLxDtZ ksyTR9LLiW0jQ== Date: Fri, 10 Jul 2026 13:57:40 +0100 From: Lorenzo Stoakes To: Andrew Morton , Suren Baghdasaryan , "Liam R. Howlett" , Vlastimil Babka , Shakeel Butt , David Hildenbrand , Mike Rapoport , Michal Hocko , Uladzislau Rezki , Toshi Kani , Catalin Marinas , Will Deacon Cc: David Carlier , Dev Jain , Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, syzbot+fd95a72470f5a44e464c@syzkaller.appspotmail.com Subject: Re: [PATCH 1/2] mm/vmalloc: acquire init_mm read lock on huge vmap promotion Message-ID: References: <20260710-series-vmap-race-fix-v1-0-5b3794c113fe@kernel.org> <20260710-series-vmap-race-fix-v1-1-5b3794c113fe@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260710-series-vmap-race-fix-v1-1-5b3794c113fe@kernel.org> X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org As per Sashiko, we need to account for x86's slightly bat... interesting ptdump of non-init_mm page tables. The fix is to take a nested init_mm lock in ptdump_walk_pgd(), which is safe as nothing depends on an init_mm lock prior to acquiring an arbitrary mm's lock. I think this could potentially be sent as an entirely separate patch, as it doesn't change what this protects against, nor the x86 CPA patch, both of which stand on their own. Cheers, Lorenzo