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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E51E0C021A4 for ; Mon, 24 Feb 2025 12:04:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 863F16B0092; Mon, 24 Feb 2025 07:04:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7EDAA6B0093; Mon, 24 Feb 2025 07:04:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 68FCF6B0095; Mon, 24 Feb 2025 07:04:38 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 4D8CC6B0092 for ; Mon, 24 Feb 2025 07:04:38 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id F07E01212FB for ; Mon, 24 Feb 2025 12:04:25 +0000 (UTC) X-FDA: 83154705690.28.64F1A8A Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf21.hostedemail.com (Postfix) with ESMTP id 47E241C0018 for ; Mon, 24 Feb 2025 12:04:24 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf21.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1740398664; a=rsa-sha256; cv=none; b=4IhLfjvFmDxkcCl2+aYfsxZIzemLolb6SWzeSH7dRkKNJcLJ8pFvZoCVMo3Omyh3VysgsK 2U829kxw17A9O2gYM/BTdmylQzaEzCZ7PlTGOrD8W+eP7URFUXq5VFELTw7xjE5GugSDw9 RB3vBdDc5ZuCf/ysfar03nmF0+qH8fw= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf21.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1740398664; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+ryFhl8+XSjDn6mgJa7GSQexAYqewTfKXy0rTXVoLUU=; b=4rlYnGrN0eQIi5bidePMYww2YP8HQBLBwmW76fDLkOrypVh7hppufBXAPqbGNS92Xq9jAM V55ZS4x5CCxlRSwL0YobDw6RIFLW1z4NriS+h0RCEqxOf3li1QzLUxPTcbvtIz+DZeax3U OXAiX9x7fL7Eqv4GyX8ayCykgS3YEZA= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 7330F5C6305; Mon, 24 Feb 2025 12:03:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BFB9C4CEE8; Mon, 24 Feb 2025 12:04:20 +0000 (UTC) Date: Mon, 24 Feb 2025 12:04:18 +0000 From: Catalin Marinas To: Ryan Roberts Cc: Will Deacon , Pasha Tatashin , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , David Hildenbrand , "Matthew Wilcox (Oracle)" , Mark Rutland , Anshuman Khandual , Alexandre Ghiti , Kevin Brodsky , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 08/14] mm/vmalloc: Warn on improper use of vunmap_range() Message-ID: References: <20250217140809.1702789-1-ryan.roberts@arm.com> <20250217140809.1702789-9-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250217140809.1702789-9-ryan.roberts@arm.com> X-Rspam-User: X-Rspamd-Queue-Id: 47E241C0018 X-Rspamd-Server: rspam12 X-Stat-Signature: o4mcm996q578wh8jg7tzd6yh3nx81sda X-HE-Tag: 1740398664-143723 X-HE-Meta: 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 uVkU1XYC 2DzjU2wSlN2ZbdxLr7cHVyK/NePbV3CNFv2+KP8/vidC3sRUVAHmyUFXL0luGuEtvh9pAHG9tuRwdi5Pd+WtQsQXQOt5vW0hi2jzrkZyKPSqKnnVxOlBIdDjxsNnDYTrOXPp+tG+P3CiNHxeZRwuIciBFIPxph9naHfnjraaEAdWwDXqjSJKqrVhcTzqMTEuZIq7jU926J/8tF/AKFJa7uWvNQlWgUz215OSS04bGnkmDolKYJlEkTEG5+Hxcm3DuGOF9EE44OUwqG6TaG+NmZ+X/fI5i+HTDj5xQMwDtqz0/6TsBKEYaMJ5ge0jtO+qs5ms0zLO0aQYtZWd4b2pq/noi7S7K9KxojoIKJrt7jN7CEiO/8myZu9JvR1IVhJ6Dvtqssp75hVyOZDCxnFea51byoGwKD5rJ5En51rsTfz8aenhXZl15FtOAARIcj7IEWNgL5NEvsEs4X9I= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Feb 17, 2025 at 02:08:00PM +0000, Ryan Roberts wrote: > A call to vmalloc_huge() may cause memory blocks to be mapped at pmd or > pud level. But it is possible to subsequently call vunmap_range() on a > sub-range of the mapped memory, which partially overlaps a pmd or pud. > In this case, vmalloc unmaps the entire pmd or pud so that the > no-overlapping portion is also unmapped. Clearly that would have a bad > outcome, but it's not something that any callers do today as far as I > can tell. So I guess it's just expected that callers will not do this. > > However, it would be useful to know if this happened in future; let's > add a warning to cover the eventuality. > > Signed-off-by: Ryan Roberts Reviewed-by: Catalin Marinas