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 296FE3C552B for ; Thu, 13 Aug 2026 17:55:42 +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=1786643752; cv=none; b=EcMRNk/hIz8OZkjl1X/Sh2kXeD+MJxUxijpqlc/1sH4wculjo1c1EN4bTEL1q6YoMUZNACa5JJuKKwqR41Ww8I0af2hlf5v4uQpa5G772SjRJ2Cb+4ihU5eh0zL+eI15nfokV5sf5KsHWbfdcM9nBaIqM3wXTFqbHzQK7nAVa+Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786643752; c=relaxed/simple; bh=vYej1wAjfc8B2YD3sV9bO2sW4gnWbXpuffkUlrpzVFY=; h=Date:To:From:Subject:Message-Id; b=eOxZqyVrdtbFqwqV8BKT8lskBxtGCp3YNrODJEQThrKhchKtyWeStaJVaSF/FzRo/C4llyDwf5jwEurE1IjiLiHzkfw8yhxYxMYbKrt7PwzGQaBabjTRKBAAPmSfbboXn8EXyLUPKbEh1JpM/jZNws6g/gbOHGqZesOWM8BZwvs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=FuVPMfDP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FuVPMfDP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 449711F00A3D; Thu, 13 Aug 2026 17:55:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1786643742; bh=yiDmwT4++08gPBlBR6Q6bKsoSGy0lVDx9usxKkLXCUo=; h=Date:To:From:Subject; b=FuVPMfDPxpOvRtbLLtbzQiJR/JV7ARS1wrSyr1yNaCZvNk/294bbdvKdrddYG+CZx ySlBndi3b5ek5mYLqEa0M0+k3nNCgllTmyTTAWsVEUd5UzjE5MZcMGzdc8TMB3iLXr hG/fTevr1f6vQHP15VQb+T4sM7hNbH6VFX0mrkqA= Date: Thu, 13 Aug 2026 10:55:41 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch removed from -mm tree Message-Id: <20260813175542.449711F00A3D@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: tools/testing/selftests/mm: add MAP_PRIVATE-/dev/zero merge tests has been removed from the -mm tree. Its filename was tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: tools/testing/selftests/mm: add MAP_PRIVATE-/dev/zero merge tests Date: Thu, 06 Aug 2026 21:21:45 +0100 Assert that MAP_PRIVATE-mapped /dev/zero mappings behave like they are anonymous. We test both unfaulted and faulted/unfaulted merges - each with the regions having page offset of 0, which would not merge if the mappings were treated as if they were file-backed. With the recent change that makes them behave as pure anonymous mappings, the merges should succeed as their page offsets are equal to their anonymous page offsets. Link: https://lore.kernel.org/20260806-b4-scalable-cow-virt-pgoff-v4-20-ab318a350404@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Tested-by: Cc: Adrian Hunter Cc: Alexander Deucher Cc: Alexander Gordeev Cc: Alexander Shishkin Cc: Alistair Popple Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Boris Brezillon Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christan König Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: Dave Airlie Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Gregory Price (Meta) Cc: Harry Yoo Cc: Heiko Carstens Cc: Huang Ray Cc: "Huang, Ying" Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Jiri Olsa Cc: John Hubbard Cc: Joshua Hahn Cc: Kairui Song Cc: Kees Cook Cc: Kemeng Shi Cc: Lance Yang Cc: Liam R. Howlett Cc: Liviu Dudau Cc: Maarten Lankhorst Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Matthew Auld Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Maxime Ripard Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Namhyung kim Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oleg Nesterov Cc: Oscar Salvador Cc: Pedro Falcato Cc: Peter Xu Cc: Peter Zijlstra Cc: Rakie Kim Cc: Rik van Riel Cc: Rodrigo Vivi Cc: Ryan Roberts Cc: Steven Price Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Hellström Cc: Thomas Zimemrmann Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Xu Xin Cc: Zi Yan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/merge.c | 104 +++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) --- a/tools/testing/selftests/mm/merge.c~tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests +++ a/tools/testing/selftests/mm/merge.c @@ -1362,6 +1362,110 @@ TEST_F(merge, anon_and_page_offset_misma ASSERT_EQ(procmap->query.vma_end, (unsigned long)ptr + 5 * page_size); } +TEST_F(merge, merge_map_private_dev_zero_unfaulted) +{ + struct procmap_fd *procmap = &self->procmap; + unsigned int page_size = self->page_size; + char *carveout = self->carveout; + char *ptr, *ptr2; + int fd_zero; + + if (access("/dev/zero", F_OK)) + SKIP(return, "No /dev/zero."); + fd_zero = open("/dev/zero", O_RDWR); + ASSERT_NE(fd_zero, -1); + + /* + * Map two MAP_PRIVATE-/dev/zero VMAs next to one another with offset 0 + * each. + * + * With these being made truly anonymous upon mapping, they will + * merge. If they were file-backed VMAs the page offsets would prevent + * merge: + * + * |-----||------| |-------------| + * | ptr || ptr2 | -> | ptr | + * |-----||------| |-------------| + */ + ptr = mmap(carveout, 5 * page_size, PROT_READ | PROT_WRITE, + MAP_FIXED | MAP_PRIVATE, fd_zero, 0); + if (ptr == MAP_FAILED) { + close(fd_zero); + ASSERT_TRUE(false); + } + ptr2 = mmap(&carveout[5 * page_size], 5 * page_size, + PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, fd_zero, 0); + if (ptr2 == MAP_FAILED) { + close(fd_zero); + ASSERT_TRUE(false); + } + close(fd_zero); + + /* Assert that they merged. */ + ASSERT_TRUE(find_vma_procmap(procmap, ptr)); + ASSERT_EQ(procmap->query.vma_start, (unsigned long)ptr); + ASSERT_EQ(procmap->query.vma_end, (unsigned long)ptr + 10 * page_size); +} + +TEST_F(merge, merge_map_private_dev_zero_faulted_unfaulted) +{ + struct procmap_fd *procmap = &self->procmap; + unsigned int page_size = self->page_size; + char *carveout = self->carveout; + char *ptr, *ptr2; + int fd_zero; + + if (access("/dev/zero", F_OK)) + SKIP(return, "No /dev/zero."); + fd_zero = open("/dev/zero", O_RDWR); + ASSERT_NE(fd_zero, -1); + + /* + * Map a MAP_PRIVATE mapping of /dev/zero with page offset 0, then fault + * it in: + * + * |-------------------------------| + * | faulted | + * |-------------------------------| + */ + ptr = mmap(carveout, 15 * page_size, PROT_READ | PROT_WRITE, + MAP_FIXED | MAP_PRIVATE, fd_zero, 0); + if (ptr == MAP_FAILED) { + close(fd_zero); + ASSERT_TRUE(false); + } + memset(ptr, 'x', 15 * page_size); + + /* + * Unmap the middle: + * + * |---------| |---------| + * | faulted | | faulted | + * |---------| |---------| + */ + ASSERT_EQ(munmap(&ptr[5 * page_size], 5 * page_size), 0); + + /* + * Map in a new unfaulted mapping in the middle with page offset 0 - + * this should merge and would not if it were treated as a file rather + * than pure anon: + * + * |---------|-----------|---------| + * | faulted | unfaulted | faulted | + * |---------|-----------|---------| + */ + ptr2 = mmap(&carveout[5 * page_size], 5 * page_size, + PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, + fd_zero, 0); + close(fd_zero); + ASSERT_NE(ptr2, MAP_FAILED); + + /* Assert that they merged. */ + ASSERT_TRUE(find_vma_procmap(procmap, ptr)); + ASSERT_EQ(procmap->query.vma_start, (unsigned long)ptr); + ASSERT_EQ(procmap->query.vma_end, (unsigned long)ptr + 15 * page_size); +} + TEST_F(merge_with_fork, mremap_faulted_to_unfaulted_prev) { struct procmap_fd *procmap = &self->procmap; _ Patches currently in -mm which might be from ljs@kernel.org are mm-add-some-missing-includes-to-mm-local-headers.patch maintainers-add-drivers-char-memc-to-mm-misc-memory-mapping-sections.patch