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 DEB9A3B14BF; Mon, 20 Jul 2026 14:41:07 +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=1784558469; cv=none; b=ByrCnWvsUyytVfs0ExkBI3BmX9dQ+lZjCYQtOCsJAjwokHsF3Ef00qw51xaQLzCroWdy98aAHTr11Sif79kTlOiYo9LoB+/jX+KED/xFbflrhGsjBG36t/De1YQWZrvbydYN9Fe41aQi39+h6nZY5ZLuDP6FA4pQZdIsmJltubc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784558469; c=relaxed/simple; bh=Ek6diG5p2xt2cOjPk+/pZ4HE6uM0F3720J7ylrqFTU4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Vy90WguiH+F+HM3CA5eRwEzpwUXePkrFivX3ptVnrKTol35LhQT+pGTGMEt1mwTYVZg6Tg41pc4SjDE1quyvETNu/XpvNIj66bQhPHIpVNa/rWXbny0DfUuqSKyry0TuLLv3Wd+PHPuUJCdU1JXBGHfv2dErp9rr8XRsce0jSS0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=or2RLRHU; 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="or2RLRHU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D01771F00A3E; Mon, 20 Jul 2026 14:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784558467; bh=mUfRyzu4r4T3oUIBL7M02RpvtLmtjfRfrYDjBQ2+mno=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=or2RLRHU8FZwq15jHcSooMC21IyoNtOp2GAZj/MrF6axYBvTNV5uuVRhkwy97o22r OtDicyiXwFPWkpvl1dOPymS/Qe/t1Y8TtBDz1vt8shmD8fc7fVZFjMsIIGq0pDAbMT NEunsqU5yT3+joKbcNdlW2MFk++0CSOSMMj9cUFxSY/qCI6bR+MzJKHdFNP81JYzWT RgoknuUd+ZMEk3ra5UvSUMW9jiyLbnWKqUF8YBlVMfNVK0LoF6bQZujd/XSteqQhyf UNDN78ZwWWQ179KcfKz6vHJsHmgTxY4KHFmfaCQgv/KM3UKNe4+dl/kRMUpPxTguPd 6fzeDCZTPffng== From: "Lorenzo Stoakes (ARM)" Date: Mon, 20 Jul 2026 15:38:40 +0100 Subject: [PATCH v2 14/15] tools/testing/vma: add test to assert MAP_PRIVATE-/dev/zero is anon 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="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260720-b4-scalable-cow-virt-pgoff-v2-14-2d549757a76f@kernel.org> References: <20260720-b4-scalable-cow-virt-pgoff-v2-0-2d549757a76f@kernel.org> In-Reply-To: <20260720-b4-scalable-cow-virt-pgoff-v2-0-2d549757a76f@kernel.org> To: Andrew Morton , David Hildenbrand , "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 Cc: "Lorenzo Stoakes (ARM)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2647; i=ljs@kernel.org; h=from:subject:message-id; bh=Ek6diG5p2xt2cOjPk+/pZ4HE6uM0F3720J7ylrqFTU4=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLLijN76quqn5K107j4fvE6K3TnS47qE7YWVRk2REkVey geW287rKGVhEONikBVTZHn+RXx/kEjYvM4L/m4wc1iZQIYwcHEKwETu3Gf4Z1JTuHbi4ju35yhz fVfL/51gdelDycsli5nXV0zqua2/I5/hn+3//4d27ee+rvoqR0m4wfroafmaoNzze3bv22idx9N gxwQA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 Now we've made MAP_PRIVATE-mapped /dev/zero mappings truly anonymous, add a VMA userland test to assert that this is the case and everything is as we would expect for an anonymous mapping. Signed-off-by: Lorenzo Stoakes (ARM) --- tools/testing/vma/include/dup.h | 1 + tools/testing/vma/tests/mmap.c | 50 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+) diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h index c5191b9718fd..47a91e35efe5 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -20,6 +20,7 @@ struct task_struct *get_current(void); #define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS)) #define MINOR(dev) ((unsigned int) ((dev) & MINORMASK)) +#define MKDEV(ma, mi) (((ma) << MINORBITS) | (mi)) #define S_IFMT 00170000 #define S_IFCHR 0020000 diff --git a/tools/testing/vma/tests/mmap.c b/tools/testing/vma/tests/mmap.c index c85bc000d1cb..b720deb4227d 100644 --- a/tools/testing/vma/tests/mmap.c +++ b/tools/testing/vma/tests/mmap.c @@ -45,7 +45,57 @@ static bool test_mmap_region_basic(void) return true; } +static int dummy_mmap_prepare(struct vm_area_desc *desc) +{ + return 0; +} + +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); + + 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 virtual 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 virtual page offsets. */ + ASSERT_EQ(vma->vm_pgoff, 0x300); + ASSERT_EQ(vma_start_virt_pgoff(vma), 0x300); + + cleanup_mm(&mm, &vmi); + return true; +} + static void run_mmap_tests(int *num_tests, int *num_fail) { TEST(mmap_region_basic); + TEST(pure_anon_dev_zero); } -- 2.55.0