From nobody Wed Dec 17 17:43:45 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E646713AD05; Fri, 3 Oct 2025 15:52:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759506777; cv=none; b=ScbGdZN2eERfBRAT1eYme7TcM/7/fs+wkjtbxERqDYyGo1SfAK0FMT7psLf9Ij3T9MY+XZbypnQlpl4adzNl/M0DKHsH5CKnf6tPzkbHjNG5wQ8+dN+p8YmjZCW3qXB92AXXrCAXm3DvJsHIBZeXahzI/fXQvmaqbS4g2zT3+uo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759506777; c=relaxed/simple; bh=asfviRWMj20n09VoR3dloG3HCRbrpqH0UwLvom6TA+c=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nsLcxSGmDiQz4dxZPt6/kgwl39fTgSt+4z7xP2I0AjtLews24r17NgHXR6THORwNYY+KBAkJyE4EX4fMcaLJ+YOq4gYdhpkfPdmQeTMQra1uJlzgLfP6erA2vnJG9JigjV7ayVkHi7qYd6FYyG4arENR99di87nX58hJVTWtnrE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8872F1655; Fri, 3 Oct 2025 08:52:40 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8D5BC3F5A1; Fri, 3 Oct 2025 08:52:46 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Amir Goldstein Cc: Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v1] fsnotify: Pass correct offset to fsnotify_mmap_perm() Date: Fri, 3 Oct 2025 16:52:36 +0100 Message-ID: <20251003155238.2147410-1-ryan.roberts@arm.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" fsnotify_mmap_perm() requires a byte offset for the file about to be mmap'ed. But it is called from vm_mmap_pgoff(), which has a page offset. Previously the conversion was done incorrectly so let's fix it, being careful not to overflow on 32-bit platforms. Discovered during code review. Cc: Fixes: 066e053fe208 ("fsnotify: add pre-content hooks on mmap()") Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Kiryl Shutsemau Reviewed-by: Lorenzo Stoakes --- Applies against today's mm-unstable (aa05a436eca8). Thanks, Ryan mm/util.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/util.c b/mm/util.c index 6c1d64ed0221..8989d5767528 100644 --- a/mm/util.c +++ b/mm/util.c @@ -566,6 +566,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned= long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff) { + loff_t off =3D (loff_t)pgoff << PAGE_SHIFT; unsigned long ret; struct mm_struct *mm =3D current->mm; unsigned long populate; @@ -573,7 +574,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned= long addr, ret =3D security_mmap_file(file, prot, flag); if (!ret) - ret =3D fsnotify_mmap_perm(file, prot, pgoff >> PAGE_SHIFT, len); + ret =3D fsnotify_mmap_perm(file, prot, off, len); if (!ret) { if (mmap_write_lock_killable(mm)) return -EINTR; -- 2.43.0