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 CC54C41D11A; Sat, 26 Sep 2026 10:41:48 +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=1790419313; cv=none; b=FqkCPaa0iOydX7op7RALVqmAT1MqlIqEErp/JqgKIeT9aYYdCA2WzaT25+Cw+TcLFq2brK8riOoX6XWqHXYL/oDXVoZBZqtyiuFL/1T4ag/IdUe3tzbcATgTi3E8lzUcCKlRRvxIjszPUo2iezXNAj2qorRm2IlLJ45cNsAaKpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790419313; c=relaxed/simple; bh=MuW0MgECKFqsgKYanDvHZ2zzAEiQ7iCtWQ9chN/jOZY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=A2JTrAliXEQtovD4lkVBLXhjyIFYZNK0Ji/XoFvw7TtXOm7MJWKdOZd1zCXUkf3MTTXDOp7FuFTvwJpkdqnRAoDmUVEcV5r9RJjku+tKdpSI7h25OiTjwJWVozR67kg7XJWwPdefPXhYaq6jHjg3zGmbe92i/gwHIbHhUGjGEyY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FOsVDr1l; 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="FOsVDr1l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABFB01F000FF; Sat, 26 Sep 2026 10:41:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790419306; bh=7INaOtP/gm2Q0CwFqGyhMMm+FXe4/enBYyOAMoEMKqg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=FOsVDr1lPbdLbth/FdBj5KzXf0oIdA6hCu9mLssK1wFzaBK7SOzL2rFrbZQ8bHdFb +NRHHqxQudc2nRYJ1z6B2okgHcmH3Qa8RHn2nNuv+gzZORsamL5057k+nLTZvMks2H CQvk+OGjt0XOPqUwSaY/SaIaxC2RNRJyuugqLkgdUKOT1BZgeVZNC79AGrl60NU85U xozIGYhzxWRg56hAQEfbIaBWA8PZWVor0VpmS3L4B8+Dgbs2ThIn5DOPdbqsDUpJjy zWbmPHl6dHArcrZuIrxNf4gxZ1w0140QygSC+R/wcRCO2cVNCT7sZ/FMNZYhQh2lCs 5YMpWKbsnVYSQ== From: "Lorenzo Stoakes (ARM)" Date: Sat, 26 Sep 2026 11:41:10 +0100 Subject: [PATCH v3 5/6] 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: <20260926-map-private-dev-zero-v3-5-d4781e84ccfc@kernel.org> References: <20260926-map-private-dev-zero-v3-0-d4781e84ccfc@kernel.org> In-Reply-To: <20260926-map-private-dev-zero-v3-0-d4781e84ccfc@kernel.org> To: Arnd Bergmann , Greg Kroah-Hartman , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Hugh Dickins , Baolin Wang , "Matthew Wilcox (Oracle)" , Jan Kara Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1881; i=ljs@kernel.org; h=from:subject:message-id; bh=MuW0MgECKFqsgKYanDvHZ2zzAEiQ7iCtWQ9chN/jOZY=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLK2L/ThnMwp/NdRf3l60KLN0u0+J8QnJbIkff2y9ehr/ qNu7dLdHaUsDGJcDLJiiizPv4jvDxIJm9d5wd8NZg4rE8gQBi5OAZjIzXiG/9nudyI6qi5MLnc9 UZecrdL263/01u7jldNfqDkUzHU8uIWR4WzMwkTmt7nexn/yZ6asiFzVbydhudHvRFBUX8SlTav FOQE= 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. Acked-by: David Hildenbrand (Arm) Signed-off-by: Lorenzo Stoakes (ARM) --- tools/testing/vma/tests/mmap.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/tools/testing/vma/tests/mmap.c b/tools/testing/vma/tests/mmap.c index c85bc000d1cb..fa73faff2262 100644 --- a/tools/testing/vma/tests/mmap.c +++ b/tools/testing/vma/tests/mmap.c @@ -45,7 +45,44 @@ static bool test_mmap_region_basic(void) return true; } +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); + struct file file = { + .f_op = &zero_fops, + }; + 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 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); + + 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