From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ADD67606A31A for ; Tue, 27 Oct 2026 00:13:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=xOHR9xp9; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Kv8t9v33 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=xzosbTAtZhW6MwCwe4dWuydc+w56Do0pdIHyzWmWbJI=; b=xOHR9xp9xHK2WGEuaDhS8Pva+2 cJ64giO8Fnil/WrJ64J+OZQidqr4u2MXVMq9CEDvEJQoLS8kosFK6kC5X2uhX8fYzM2ZvRMDlV3Iq ZBZDz8jjjkhBChBUhTaceK/5XWc7nQtXpcWJowomQWQuvpdgvrQ/W25TFShPQlaaJ6g2Phe0ESFrK anFw8DupWOUd6fF4Nn5cxDDySa3p4l2IHlAn8VC/ZTAru71AowyitxoMaLuy8ExPh+5elTTF/cQau LxGCpCfe8lVpV4mwnCwF5kek0hxNXKsMKnir/RN4mQ8Cyxpf0XxvuI4hk9kTP4T69Bb1DdgDZ+HD5 +NaxFDyA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUpD-00000003Vy0-1dR5; Tue, 27 Oct 2026 00:13:59 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUpC-00000003Vwu-0E04 for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:13:58 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 7D546601FB; Tue, 27 Oct 2026 00:13:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DA2E1F01825; Tue, 27 Oct 2026 00:13:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793060037; bh=xzosbTAtZhW6MwCwe4dWuydc+w56Do0pdIHyzWmWbJI=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Kv8t9v334jctyul1aOPDOUGxRmeYVdmAISD3cKHfc85hxho+Bvqz2GMAjPWsd3LaL +C+TlJZjHs2jLj/jOU3dhifiH9V8jN6y3F+euSRXpbvDaU1SODbAyEnP75I+Y9zL4W KsszBOK52P3W+RmHm7yjuEPak6XbA3UAxGnTXzY0gr6MGUkhEn5fEBAOeWtDtdrYYc bmAjDYsWP2jSRUxuNlS9VQKGMrnTzB8QZuKPOQCdrQ5tx4dMyipCWIFTeJCBHQ2zxT Y4hU2CPJQUjcAyJ9Jm/Piq+tzX9g51UJUgiLlxEhSS4t6Hmt0yxDbK4WqsRyakHltl dqoJC1NzoGpWw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 35/46] mm: fix unmap_mapping_range() beyond 4 GiB on 32-bit To: =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Andrew Morton" , "Johannes Weiner" , "Michal Hocko" , "Qi Zheng" , "Shakeel Butt" , "Lorenzo Stoakes" , "Kairui Song" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Baoquan He" , "Baolin Wang" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , =?utf-8?b?TWF0dGhldyBXaWxjb3ggKE9yYWNsZSk=?= , "Jan Kara" , "Zi Yan" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" Cc: kexec@lists.infradead.org, "Josef Bacik" In-Reply-To: <20261027-fixes_core-v1-35-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-35-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:13:53 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > From: Josef Bacik >=20 > Commit 9eab0421fa94 ("mm: fix unmap_mapping_range high bits shift bug") > made holebegin and holelen unsigned before they are shifted, by casting > them to pgoff_t. That is an unsigned long: on a 32-bit kernel the cast > cuts off the upper half of the two loff_t values, so a hole which begins > at 4 GiB or beyond is taken for one in the first 4 GiB of the file. >=20 > truncate_pagecache() passes the new size of the file and asks for private > COWed pages to be unmapped as well. If a file of 6 GiB is truncated to > 5 GiB, everything from 1 GiB on is unmapped, and what a process has > written to a private mapping of the range between 1 GiB and 5 GiB is > lost: it reads the contents of the file again. >=20 > Where the range has an end, the wrong range is unmapped instead of the > right one. The page cache copes with that, as it unmaps every folio that > it removes. The callers which only have unmap_mapping_range() to get > rid of user mappings do not, for example drm_vma_node_unmap(), whose fake > offsets reach beyond 4 GiB on 32-bit, and revoke_iomem() with physical > addresses of more than 32 bits. >=20 > Cast to u64 instead. Nothing changes for 64-bit kernels. >=20 > Fix generated by an LLM and sent by Josef Bacik in private. >=20 > Fixes: 9eab0421fa94 ("mm: fix unmap_mapping_range high bits shift bug") > Cc: stable@vger.kernel.org > Signed-off-by: Josef Bacik > Acked-by: Lorenzo Stoakes (ARM) > Signed-off-by: David Hildenbrand (Arm) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261027-fixes_core= -v1-0-6f74bec9a5bb@kernel.org?part=3D35