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 B7D53606A321 for ; Tue, 27 Oct 2026 09:44:44 +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=JXEbY6rG; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=gNzLclvd 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:To:References:Message-Id: Content-Transfer-Encoding:Cc:Date:In-Reply-To:From:Subject:Mime-Version: Content-Type:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=+gg4vR3fmVnG5maxAfXCLUk2K7fJTSLOiXsuwQyP13c=; b=JXEbY6rGfsz7Lt SLkJE69UF7VRK3vuK2lwuFo8sPh5DSiQXt1cN3qNUkYIm5EJqroy4+le77SmnyxhZ+dbi1iTuxIow MpnmF2rPnTN58AHmodRYh9i9AQQHrIfRvIS3i3Jy99/8I8jwLDoIIobLv7VkooRlgTFG5OrjgIiqF kMja1LZd2qFoMZuxkxWprmwRZMTiKzCiDzJbRlrreBmqaajfR5c5lk3CWavf6XsTCbBITC5XKvKzB 7tkjbaJxcsf/xnIkRbGaWrqXwERECNnuiIbovNqC+No7Q41E9c6BIhEfGkvFlcIz/Y4hvZv/nPt4H EujWGC7/04D3D9y0tp3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdjY-00000004CXV-1Pba; Tue, 27 Oct 2026 09:44:44 +0000 Received: from out-151.mta0.migadu.com ([2001:41d0:1004:224b::97] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdjV-00000004CWC-1SKz for kexec@lists.infradead.org; Tue, 27 Oct 2026 09:44:42 +0000 X-Envelope-To: kexec@lists.infradead.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: kexec@lists.infradead.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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261027_024441_527672_DBE3317B X-CRM114-Status: UNSURE ( 9.86 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , 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 > 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.