From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794273806; b=FrqvAlqrh+kbdNPvdNs0AOQE4rN37D2UvZgbo4QwA6y7KVZaOgJ+xxIHfDje49b3T8cZ 83pETXaKVidkrHYb5JX2IO7JVrDUuu1u+yi/tOMpLugljxtwL0SJaaLH7IoP6Bdyqjkxu kYbK5/bWNUY4TydhOF2axQqVeXY9Ap2r5FSMv7VmtTbH8oWeVDczBZc1PtTN9DAFKnOIh SBvVnmvXypz0gRMYdxXhOSA6mqFOpTx1WjqLwfAyv+y/sVPikvD/1EnYcQo9pGPTtb3kr e8sA1SKM0/D5w3OMngn9wE9kgoOOQjWnSyzVgseH3YHJXMz9NrZMwNvUika1E4UKSuA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273806; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=eBO6p7EfrF8TLvU28GBeZs/T00esIKcQUcDe7XIgfN0=; b=IHZYjx8dxhZdLIFyVCmUIf5Bem/FZmOBkfG+5B6EM87/CCki95OEJHg2jEP7TJUBt2/m riLBbTpF69Lb8YZAnuZSsznDs5Tk30A1gfZC+kWe2jeLLxC1h78376fVk0nrIwSFChS6B GXGgdm9nLGwwGdbqIlRQwyaCYJc9yVaIMUXumWu/NA3cTMRsdwJPa+waLOi9hdi13yAmJ yGAbJeH5nD0hrV4XVPko0ZtxYrPkKjTWpfgn18FD7HHlXQgox1/G/Bt3EfQ8ucYQuvqQf eHkwUlNf4QjRcn8Oa63UhuHY4tSCmrtaV4zSaSrlQBvWD1cKHJ93eVYRaPrHzdTiz6g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RuAuYjYx; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A25876071843 for ; Tue, 10 Nov 2026 01:23:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RuAuYjYx Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F13F1F0089F; Tue, 10 Nov 2026 01:23:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273805; bh=eBO6p7EfrF8TLvU28GBeZs/T00esIKcQUcDe7XIgfN0=; h=From:To:Cc:Subject:Date; b=RuAuYjYxJpTOKSDJiipRSJdOpUtCWV83lTLvlykZBfV2m8pLqRqsu0MJcTaZvIAL/ yXaywWtpPuw9y2/TLqLqDVPlP74e95TtGG7H9cPnqN8ZozPnWhKPbvppPMe3+SyLsj tOXZlX4Fsa44Xzj5YunuSlRs/hS0V7ESuASuAVrvxaRjlwO+YPd5WoVnVffJrHs6bA Vr1KNnvD87xzBqXtgrOLM0vI9wh6+wfCrAlVkfRdPnystNrvXRNcLn+JxlNlden3jf ojYE9WqYFKJsFV64SkoCHLcXxTDe7IKIpeY0ov8GDbBzNVfLjRx/SXk4pQHKfrtaY4 AKrd5XS+VuX9g== From: Sasha Levin To: david@kernel.org, ljs@kernel.org, muchun.song@linux.dev, baohua@kernel.org, usama.anjum@arm.com Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mm/gup: check for overflow when converting nr_pages to bytes in GUP-fast" failed to apply to 5.15-stable tree Date: Mon, 9 Nov 2026 20:23:23 -0500 Message-ID: <20261109202323-failed-5.15-21a3888d3d2f@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 21a3888d3d2f87b7f15ccea1f0befd57346fe899 # git commit -s git send-email --to '' --in-reply-to '20261109202323-failed-5.15-21a3888d3d2f@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 21a3888d3d2f87b7f15ccea1f0befd57346fe899 Mon Sep 17 00:00:00 2001 From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:51 +0100 Subject: [PATCH] mm/gup: check for overflow when converting nr_pages to bytes in GUP-fast 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. Users such as RapidIO's rio_dma_transfer() can derive such page counts from a 64-bit userspace length. Let's just check_shl_overflow() to reject any such overflow with -EOVERFLOW early. Fixes: c28b1fc70390 ("mm/gup: reorganize internal_get_user_pages_fast()") Cc: stable@vger.kernel.org Reviewed-by: Lorenzo Stoakes (ARM) Acked-by: Muchun Song Reviewed-by: Barry Song Tested-by: Muhammad Usama Anjum Link: https://patch.msgid.link/20261031-fixes_core-v3-22-d6437171ecc3@kernel.org Signed-off-by: David Hildenbrand (Arm) --- mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 1c2ac7c66c309..ba4907b352323 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3225,8 +3225,8 @@ static int gup_fast_fallback(unsigned long start, unsigned long nr_pages, might_lock_read(¤t->mm->mmap_lock); start = untagged_addr(start) & PAGE_MASK; - len = nr_pages << PAGE_SHIFT; - if (check_add_overflow(start, len, &end)) + if (check_shl_overflow(nr_pages, PAGE_SHIFT, &len) || + check_add_overflow(start, len, &end)) return -EOVERFLOW; if (end > TASK_SIZE_MAX) return -EFAULT; -- 2.53.0