From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CA849606A322 for ; Tue, 27 Oct 2026 02:06:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key, unprotected) header.d=surriel.com header.i=@surriel.com header.a=rsa-sha256 header.s=mail header.b=CWZKUMOl Received: by kanga.kvack.org (Postfix) id D27BB6B05B7; Mon, 26 Oct 2026 22:06:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CD9A96B05B8; Mon, 26 Oct 2026 22:06:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BC7A46B05B9; Mon, 26 Oct 2026 22:06:04 -0400 (EDT) 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 92A9D6B05B7 for ; Mon, 26 Oct 2026 22:06:04 -0400 (EDT) Received: from smtpin26.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 272301405E6 for ; Tue, 27 Oct 2026 02:06:04 +0000 (UTC) X-FDA: 85366765848.26.75A2174 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by imf23.hostedemail.com (Postfix) with ESMTP id 79D86140004 for ; Tue, 27 Oct 2026 02:06:02 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=surriel.com header.s=mail header.b="CWZKUM O"; spf=pass (imf23.hostedemail.com: domain of riel@surriel.com designates 96.67.55.147 as permitted sender) smtp.mailfrom=riel@surriel.com; dmarc=pass (policy=quarantine) header.from=surriel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793066762; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=BbcsaSvYmqsc1/PGogALmAlsxQ4NtVNgPQ1FxMhmi+A=; b=7X9WClx/OfytirEaCcrXIugr+jjnRCrA+dd6171k+GxXq25rbp1hgyCnrw48WfrFr5m61H Db4FgIBrQ5dZSYTY6Z4SsKY4QBNfwvC8xVqKJjmnPVnkx8IGzgr81GHV6IO8DzN4tjGDeZ G9uFq9sOIu5ri+3ZvrZju4+hruLqrMg= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=surriel.com header.s=mail header.b="CWZKUM O"; spf=pass (imf23.hostedemail.com: domain of riel@surriel.com designates 96.67.55.147 as permitted sender) smtp.mailfrom=riel@surriel.com; dmarc=pass (policy=quarantine) header.from=surriel.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793066762; b=Xu0vnVEX/PrZOIpAlq8g6O3Z4FychAYbhaM2AeG4M2L/oMVZwj9yRE5B2qg2L3A1+1PudS Tbq11IUwDpIdCaoJIqoSR3xcgcO01IyaWnfjh08PDByG0KzISTKvx8Aj7vRWJU5t+Qc+QA aHgH6S0g0nBccnGv/uEHquMN+uYKNyI= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID; bh=BbcsaSvYmqsc1/PGogALmAlsxQ4NtVNgPQ1FxMhmi+A=; b=CWZKUM Olnx3u/Gk5d/OR91etCdue5a5CeEvh9PUqUSqSygUk5of/q0VBUBLnXBtQ2IAvjkhbniPBjcGJ5AJ zBfQQUrA0ZeKI7TGX302NhHs/ur3FPzRcq5M6b0MbQR0vP9icJJX5f5CLh/ck9GLTlhxJTH3OYQdd WvMY6xVWwNwR+GZMzxMuGji7f82nyk0ZKOcdh6DgF0SppBH9V107GJT6RjHLvk6VFYHa2mO8AqRKg r0D6xxl2JO9boBueLIeID4FZrS8rSfqex+cOpROWqy4bTb6t0CjFI5zmTuuIJNeHNGcWzLHLf97l7 vOiE2PSWsmxrt/oipmdtcnhFJauQ==; Received: from [2601:18c:8100:a0e0:2541:b86e:2586:d219] by shelob.surriel.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.99.5) (envelope-from ) id 1xLWY0-0000000B0qk-3U0e; Tue, 27 Oct 2026 02:04:20 +0000 Message-ID: <35420f2a3d5f3af10cd88fd9e3a977b4e17a0476.camel@surriel.com> Subject: Re: [PATCH 03/46] mm/memfd: check for real shmem inodes before accessing shmem state From: Rik van Riel To: "David Hildenbrand (Arm)" , 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 , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , 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: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Chris Mason Date: Mon, 26 Oct 2026 22:04:20 -0400 In-Reply-To: <20261027-fixes_core-v1-3-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-3-6f74bec9a5bb@kernel.org> Autocrypt: addr=riel@surriel.com; 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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-2.fc44) X-Archived-By: MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 79D86140004 X-Spam-Status: No, score=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Stat-Signature: af99pg3y5mfkjimb5zo4e943yf6q36rz X-HE-Tag: 1793066762-39697 X-HE-Meta: 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 2UDwiYjI 02VYmpikw8mEAU2N5eQrG2Kg2le1Uu3nLxDndkfQCcyqwC6uRqXCd4l0qhsxQadBYlWxMTfHroxQeK0kXSb884ZY4YlHGPgSQ83lnJLn3wdQJeq6DTIvSKjVFah3I268XP7Bwh4ZSZmPzjncDN9fTzBrcm8g3ylA8N3WomDQCd3pWKo84kL1r86RQELG1+tsewpOsmYQ/xGJe6IHvVRnfdj3UA6NPX3+iUwsbh9/m2Z0pgy1bpKlbmQGWEJXUMCdgD9H0DRjva7XBGxwFinsaAiDunqFDxsc/fwFniB5THeJ/UpS4cu+tfphZ4WvavFOIRjvutqqrCV38er5Z5Lnj0oHVx+wZNgVb8ucfh4WK1FEdHBomMpoSWtW9dlXOLmZ1ViyRVZsoNseE0ttlaMYIdpZBwurgCa6qArsP+84lNr6XFFhIc/O/Hh+u8A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, 2026-10-27 at 00:17 +0100, David Hildenbrand (Arm) wrote: > shmem_file() only checks a file's backing mapping. That mapping can > belong > to another file, as with a Coda file backed by a tmpfs container > after > mmap(). It does not establish that file_inode(file) is a shmem inode. >=20 > Seal handling and memfd preservation use this check before accessing > shmem inode state, so they can access an inode of the wrong type. >=20 > Add file_inode_is_shmem() to check the inode's file operations in > both > paths. This identifies regular shmem inodes, including those used by > memfds and ordinary tmpfs files, independently of wrapper file > operations. >=20 > Fixes: c49fcfcda8b5 ("mm/shmem: update file sealing comments and file > checking") > Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd") > Cc: stable@vger.kernel.org > Reported-by: Chris Mason > Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Rik van Riel --=20 All Rights Reversed.