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 3C241606A31A for ; Tue, 27 Oct 2026 09:44:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=gNzLclvd Received: by kanga.kvack.org (Postfix) id 53DA56B066E; Tue, 27 Oct 2026 05:44:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 515336B066F; Tue, 27 Oct 2026 05:44:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 42D056B0670; Tue, 27 Oct 2026 05:44:43 -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 23CD86B066E for ; Tue, 27 Oct 2026 05:44:43 -0400 (EDT) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id B777E140963 for ; Tue, 27 Oct 2026 09:44:42 +0000 (UTC) X-FDA: 85367921604.17.33FFA1C Received: from mta0.migadu.com (out-121.mta0.migadu.com [91.218.175.121]) by imf08.hostedemail.com (Postfix) with ESMTP id AAEDB160006 for ; Tue, 27 Oct 2026 09:44:40 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gNzLclvd; spf=pass (imf08.hostedemail.com: domain of muchun.song@linux.dev designates 91.218.175.121 as permitted sender) smtp.mailfrom=muchun.song@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793094280; b=ntNG2AWDeKB2Mc+LeIACOUGkJn1aW8wup6S2DKn6WJjpW4vpUjWT7+OwKG7fnvXOs7S6SU gpc1VQgqei+VoFhXVZmWkwykHv4XQCx74OCeGioXmEWh0gCCpXly46OyBOOwoAPvpiyMv+ xJGjFTN09P+hsAFfli0fb/fZWyd3bok= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gNzLclvd; spf=pass (imf08.hostedemail.com: domain of muchun.song@linux.dev designates 91.218.175.121 as permitted sender) smtp.mailfrom=muchun.song@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793094280; 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=+gg4vR3fmVnG5maxAfXCLUk2K7fJTSLOiXsuwQyP13c=; b=RF+HriHYMbeBczcr3GK6n4Fpm/dQlroliJHO38YDGz09/rXh27y8+vq5eiuBFdkvToVwaJ cxVg8S/xvP1l7rrNHnh5FS3DI2mzD6YgrmhsqTq3tPgZ3A11qHuC8tfFKpFBYCF6BFvdxN QQVT+kcM5MNUlRtGaPEwJnhUCugHbAs= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=+gg4vR3fmVnG5maxAfXCLUk2K7fJTSLOiXsuwQyP13c=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793094279; v=1; x=1793699079; b=gNzLclvdu9m1gyvv0pSAmIjLpny2p0E4lbCIgdharCug0gruLgksOqUPZHjJjYvzCRrMZEqZ BhMKbq2Tt5gWy1KtiCZ7kwh9wWR1Po4osGjY8vUU/f1n8v2J0dH2J2mW12ceWGdmUh6+8ngwqDK /m6YU/MKq9hmnUlKgC7g+22I= X-Envelope-To: linux-mm@kvack.org Received: by mta12.migadu.com with ESMTPS id d06deef23f08d73b; Tue, 27 Oct 2026 09:44:38 +0000 X-Mizu-Trace-ID: d06deef23f08d73b X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=us-ascii X-Archived-By: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3901.100.1.1.12\)) Subject: Re: [PATCH 22/46] mm/gup: check for overflow when converting nr_pages to bytes in GUP-fast From: Muchun Song In-Reply-To: <20261027-fixes_core-v1-22-6f74bec9a5bb@kernel.org> Date: Tue, 27 Oct 2026 17:44:07 +0800 Cc: 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 , 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 , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , 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 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-22-6f74bec9a5bb@kernel.org> To: "David Hildenbrand (Arm)" X-Mailer: Apple Mail (2.3901.100.1.1.12) X-Rspam-User: X-Rspamd-Queue-Id: AAEDB160006 X-Stat-Signature: fyyug339u77w9a5bn1o453yinpa5t7fo X-Rspamd-Server: rspam01 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1793094280-816461 X-HE-Meta: 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 zzwLkHc/ s3joztbKoFj46vGl0w+9HL5ovAh2kQbobG064uZ2QDMswimSNSrbwO4ttABvAYCRE80dm5nXqloFM5FQzPZTAzVyyEeU2oAbOyEtpDySbmXwIrJsfTpO7s6S3J/bVYWXtd4aHKwDAPOfNz1QfbloAK9Vxo79+p5Usk04TPnIIFH8ZiuoIJAysFvi+EyikXJaXoCx6Jft6jfuXjUYtiyLVoXJocP79paJuxqMd7xuBNqYFdSau+IrOrnY04B6H0LihImXfwERAMi0KbULqBpi6GN9ux27Rp95YFzj5ZcoJambNT7Hma7eZtCKRlN72LqWmW40/8+7fVAcH6Qnna/59UFtKLE+XNYJJRQyMLSMPAHI1anJ1bZ4eBJWnihVwSHP6Q8kSK6bCMJHrrEvSTtqYnpVoBQ== 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 Oct 27, 2026, at 07:17, David Hildenbrand (Arm) = wrote: >=20 > The overflow check in gup_fast_fallback() only covers the addition to > start. The preceding nr_pages << PAGE_SHIFT can already have truncated > the length on 32bit. >=20 > Users such as RapidIO's rio_dma_transfer() can derive such page counts > from a 64-bit userspace length. >=20 > Let's just check_shl_overflow() to reject any such overflow with > -EOVERFLOW early. >=20 > Fixes: c28b1fc70390 ("mm/gup: reorganize = internal_get_user_pages_fast()") > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) Acked-by: Muchun Song Thanks.