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 7E9D8606A31F for ; Mon, 26 Oct 2026 23:24:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=OzH8AW7I Received: by kanga.kvack.org (Postfix) id 90FED6B05D5; Mon, 26 Oct 2026 19:24:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E7516B05D6; Mon, 26 Oct 2026 19:24:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FDAB6B05D7; Mon, 26 Oct 2026 19:24:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 5A9296B05D5 for ; Mon, 26 Oct 2026 19:24:33 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id CE619C08A5 for ; Mon, 26 Oct 2026 23:24:32 +0000 (UTC) X-FDA: 85366358784.30.8B1B711 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf13.hostedemail.com (Postfix) with ESMTP id 12D672000B for ; Mon, 26 Oct 2026 23:24:30 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=OzH8AW7I; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793057071; 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=MUiVnQIcW4HK+Vvqa5OhN89hQ5i9YryKSTF3EOLnRhs=; b=SPKN+BFHgGptBALhQyU4FGyR6egKdt1u+nVdVxIbASHtUX7ZF+FzKa2quHuSvijGcCclhY z+Ykv3alNhNG/rNNfzjV1PIPgqk4PjwJxKnuU/7653UwzW7tsbMQUcoULHArQcQzzQnhKe QaG4voXqkBIvIFz64bmEhwWx37vd/ZE= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=OzH8AW7I; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793057071; b=cUAnHPwHvP1laQ4Ey3pyeIPZvlpYfD1xvE0lZkoChrNDVftagILXN+2RED7g5eaz7Ux06h KosU/trdTuyNr3Pjgj8xPydve+oQMVNzFFulDp4xc1eK5DOOwuhV4mbu6sV7cRVoW1+GbO 4IJXolpqIRTuK/xRtgUJ9hWaPW4hlUE= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id A341C601F9; Mon, 26 Oct 2026 23:24:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19DC01F01825; Mon, 26 Oct 2026 23:24:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793057070; bh=MUiVnQIcW4HK+Vvqa5OhN89hQ5i9YryKSTF3EOLnRhs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=OzH8AW7IZVGSLh2s2JrXn3LgfDvl1ZX4yFb3GlfsKgz8zoruMSoZEux9/uq7Tk7sm cs4Oevuzm9hv19FFmzb4oVFDDyN8hTsXOa6ga9Wfsm5s0IDEHvgPHKHT1iRlEt6Wlx jX+TKAvX+UWsfR/O6g1EGXksf6/NAU5KAIgRyfAIxs3u0nD6husexzjL6i0H+JmNDj QvoT1xFpiuuavcAk/OvUsImVM/yKW2pqjZDDZvkv/sFj6K5bneJ1bUwoy5GawuHUzZ 931Cja01VhM36lJwgGvGp6aGe8/8ws02QJV+KXzzxA8UueMTlx/UmBS8gk/lw+F0G7 w2duGXjGqq0LQ== From: "David Hildenbrand (Arm)" Date: Tue, 27 Oct 2026 00:17:41 +0100 Subject: [PATCH 21/46] mm/gup: fix out-of-bounds write for nr_pages == 0 in GUP-fast X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261027-fixes_core-v1-21-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> In-Reply-To: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> To: 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 , 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, Chris Mason , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1165; i=david@kernel.org; h=from:subject:message-id; bh=+4EllZ1FmTDP2PkVD3jcp4reP8xmeyVcibo3mkhoq5k=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLu358669na3pAFl6/pLlittcCkyfDvlTqOwCWbPfX87 u3WdpqU2VHKwiDGwSArpsgSFHzf4OXLdbXVbnzMMHNYmUCGMHBxCsBEohMZGW49v/1k3cwERfmt n7+fPaFx4sZu2c8NIUqvN6qeE//yxBuoYsd97QN6BzL9n+U45fx9aXrcwfOcrdWLPY5TbjzqWTN 3FwcA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 12D672000B X-Rspam-User: X-Stat-Signature: a8n7sa85p4ggmmn4dcqramj1bc5mehij X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793057070-887222 X-HE-Meta: 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 uETrxlc/ zlj6RJzJtZNH9f3/idRhhrRD0znUYRWii70+5F6reKdp79OPtiI3dXuE+9F4CdytsAdgXfzcmQ6nOLLYEi8HadgcI13axZNdqPOhBUB/NdogkDff8m8eFfuFBZjCY0PtuPvDV3oSEy/dG7/gHBuF8ZRp29DRX47K7fab5/8eSY/xHuC91km6zvjKDUFcofgn3RmofBlmU5zmzLLxkMmgZOMdluHRpDNAetVPM72NLCv11iD6O+/E0wNGDNLzIUHliqSr45eux1rzHdEpo2Hi+LZC81v+xQ86TGkxpUUElIeeuxnC3mQ7dUNqE8+9IgWOcha9X1CczxqJN2w/+ifPkClYBxVjPsTG5xLkGviQmgEU5yNY= 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 From: Chris Mason With nr_pages == 0, GUP-fast still enters its page table walk and can write past the caller's page array. The old end <= start check caught empty ranges, but was replaced with an overflow check. Users such as OrangeFS can pass a zero page count derived from a userspace-supplied length. So let's return zero for nr_pages == 0 before starting the walk, just like GUP-slow. Fix generated by an LLM and sent by Chris Mason in private. Fixes: c28b1fc70390 ("mm/gup: reorganize internal_get_user_pages_fast()") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Signed-off-by: David Hildenbrand (Arm) --- mm/gup.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index 47e7ae152cdf1..9906965893431 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3204,6 +3204,9 @@ static int gup_fast_fallback(unsigned long start, unsigned long nr_pages, FOLL_PCI_P2PDMA | FOLL_HONOR_NUMA_FAULT))) return -EINVAL; + if (unlikely(!nr_pages)) + return 0; + if (gup_flags & FOLL_PIN) mm_set_has_pinned_flag(current->mm); -- 2.43.0