From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0C02477E4F; Wed, 12 Aug 2026 18:09:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786558145; cv=none; b=e7V80HsfUhUL+zIGaBEBQN0MpG/sLQOhE5YGRiq76yWFEPlZX4WhzzICcf6qBIb5Fd1uDFykZ5WP9A1Ai0SVfv4gP5jvQ2xPOyVba6iKJ2SLjKgkeLHtjk9gTZTDb3EQX4yaDajVwks9uE2vrkjN9EsYgV8Z7bHuDqm61uLsQwU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786558145; c=relaxed/simple; bh=Yi5far2ZKXnrZTlfHu9Izikx3SvheQpzfjRHuGQy+xY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hhlEuUeHi6j6kJiRovbFy0NlqR6RSB1kRMmZRRtVRaBwXpW+AHcrW2tBfOw3gj4oUt1/gsitHWw54w8tP001wfo69huuM5+yFbuPIDMgvnJmF05NbZ+h+T2i1tXrRhIEaurB+xzYJ0zoLu5mENX6TJq8S1yscqhaL3+PWQixHTM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FPZqAbLL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FPZqAbLL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D7B41F000E9; Wed, 12 Aug 2026 18:08:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786558144; bh=/4wKYM9MxtqgdWEMOzwNt0V2ekWexcqa8GGAN8Nt6p8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FPZqAbLLWRIKnNz+QQXKAqF9IVzq9IiefDRz1565tIbl/YT7GDxa0hVfpHvtuPJOv 21Vj/7WrU8+huUaZKOGhGAzGzQWLjfUMZVZt2ff4LGvtC2SCdGUaGADsrWisnU+XWO beIMV93LtMwcdcrt2YjPyUDHzLIhwRqnV3IEVkVEGVWMozBMT+LElOjqy90TkkKs+N ZQx0XKNVpk1LWcEBgnepPPW8ZiW8sWwUJy3aW30MjDw6aprydwCd/wc7rmQd1wt6sB wuQg/3oKhwJjGNZDGpj090xIWx/Y23Nxl83v8P3inLlBDasM7ar0kQeBrH3IL7iRZm rzZ5tMbMJv3NQ== Date: Wed, 12 Aug 2026 19:08:29 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , "Matthew Wilcox (Oracle)" , Jan Kara , Miaohe Lin , Naoya Horiguchi , Rik van Riel , Harry Yoo , Lance Yang , Kees Cook , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Usama Arif , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Peter Xu , Xu Xin , Chengming Zhou , Arnd Bergmann , Greg Kroah-Hartman , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Alex Deucher , Christian =?utf-8?B?S8O2bmln?= , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Boris Brezillon , Steven Price , Liviu Dudau , Huang Rui , Matthew Auld , Thomas =?utf-8?Q?Hellstr=C3=B6m?= , Rodrigo Vivi , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , Jason Gunthorpe , John Hubbard , Muchun Song , Oscar Salvador , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v4 19/20] tools/testing/vma: add test to assert MAP_PRIVATE-/dev/zero is anon Message-ID: References: <20260806-b4-scalable-cow-virt-pgoff-v4-0-ab318a350404@kernel.org> <20260806-b4-scalable-cow-virt-pgoff-v4-19-ab318a350404@kernel.org> <5d1a35d2-8541-44d5-8958-1efa9773d7bb@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5d1a35d2-8541-44d5-8958-1efa9773d7bb@kernel.org> On Wed, Aug 12, 2026 at 07:17:39PM +0200, David Hildenbrand (Arm) wrote: > > +static bool test_pure_anon_dev_zero(void) > > +{ > > + const vma_flags_t vma_flags = mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, > > + VMA_MAYREAD_BIT, VMA_MAYWRITE_BIT); > > + const struct file_operations f_op = { > > + .mmap_prepare = dummy_mmap_prepare, > > + }; > > + struct inode inode = { > > + .i_mode = S_IFCHR, > > + .i_rdev = MKDEV(MEM_MAJOR, DEVZERO_MINOR), > > + }; > > + struct file file = { > > + .f_inode = &inode, > > + .f_op = &f_op, > > + }; > > + struct mm_struct mm = {}; > > + struct vm_area_struct *vma; > > + unsigned long addr; > > + VMA_ITERATOR(vmi, &mm, 0); > > + > > When we go with a zero_vm_ops this gets a bit simpler (see schloppedi-schlop). Obviously will have to replace this with something else that just sets anon in an mmap_prepare callback once I drop 17/20. > > > + current->mm = &mm; > > + > > + /* > > + * Map a MAP_PRIVATE-/dev/zero mapping at address 0x300000 with a page > > + * offset of 0x10, which we expect to be reset to the anonymous page > > + * offset. > > + */ > > + addr = __mmap_region(&file, 0x300000, 0x3000, vma_flags, 0x10, NULL); > > + ASSERT_EQ(addr, 0x300000); > > + > > + /* Assert that it truly is an anonymous mapping. */ > > + vma = vma_lookup(&mm, addr); > > + ASSERT_NE(vma, NULL); > > + ASSERT_TRUE(vma_is_anonymous(vma)); > > + ASSERT_EQ(vma->vm_file, NULL); > > + ASSERT_EQ(vma->vm_private_data, NULL); > > + /* Expect anonymous page offsets. */ > > + ASSERT_EQ(vma->vm_pgoff, 0x300); > > + ASSERT_EQ(vma_start_anon_pgoff(vma), 0x300); > > Yes, that looks good to me. > > Acked-by: David Hildenbrand (Arm) Thanks > > -- > Cheers, > > David -- Cheers, Lorenzo