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 BFCB42DC334; Thu, 25 Jun 2026 13:08:12 +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=1782392894; cv=none; b=C87Kj8sClJ1rKPxIYEreJ3HHhHGNxbW9q8V2ITUJJrQasZXMjLOSrDbO+uOZBUE1NsK6jQ0U/3X44mm4YAJrwYVyCbVYB1B+iGkFVXLABE1py+oVNLx+OALWWBdYQPKAcQ1a99rdLfej5hU1lVdxv41ZlaJLPAqG1ompcqytpmM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782392894; c=relaxed/simple; bh=pfZfuQEHDP42dBNoHHZhyveWire0DtYNviasEQVUCmQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PiJVfTfjdjcs+hdiInQ5IUAYYMyN0RcISN8uU0ttRIY3gnMN4zrvpWKEBFMPS3v8EYAYWpmwu1K3REQKAomPH8uZWDp8RHTLIje6tLiLPfqg+ieDBSv5qlmFuhyk3v/68/FNhPRdSLOk/8SEZmTL2AZ9LDtjs0dMtsSBweGN8Y4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gYKz/8Jp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gYKz/8Jp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1BC571F000E9; Thu, 25 Jun 2026 13:08:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782392892; bh=g2DoFrZJUjSKa78Fnxen5WaXlPtYmsR7htSp5vKDxvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gYKz/8Jpw1dnnLnkfPJpXnjG8r1ejw0kZuhLGZu2gE5UHQSwm8qe5Yy8P3V7c1msn KnSwpMnh51korhQM27nVaqVwcCZpYWefQjkVvO2ru4GxSjvFw3ZFKsAypJTHD4dWoi FZhwgbNwLFmBgSSr4T9ccyveHVtu7v5cj3pVjksE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lorenzo Stoakes , Andrey Vagin , "David Hildenbrand (Red Hat)" , Jann Horn , Liam Howlett , Michal Hocko , Mike Rapoport , Pedro Falcato , Suren Baghdasaryan , Vlastimil Babka , Cyrill Gorcunov , Andrew Morton , Ahmed Elaidy Subject: [PATCH 6.18 41/60] testing/selftests/mm: add soft-dirty merge self-test Date: Thu, 25 Jun 2026 14:03:26 +0100 Message-ID: <20260625125651.704240577@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260625125645.554579168@linuxfoundation.org> References: <20260625125645.554579168@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lorenzo Stoakes commit c7ba92bcfea34f6b4afc744c3b65c8f7420fefe0 upstream. Assert that we correctly merge VMAs containing VM_SOFTDIRTY flags now that we correctly handle these as sticky. In order to do so, we have to account for the fact the pagemap interface checks soft dirty PTEs and additionally that newly merged VMAs are marked VM_SOFTDIRTY. We do this by using use unfaulted anon VMAs, establishing one and clearing references on that one, before establishing another and merging the two before checking that soft-dirty is propagated as expected. We check that this functions correctly with mremap() and mprotect() as sample cases, because VMA merge of adjacent newly mapped VMAs will automatically be made soft-dirty due to existing logic which does so. We are therefore exercising other means of merging VMAs. Link: https://lkml.kernel.org/r/d5a0f735783fb4f30a604f570ede02ccc5e29be9.1763399675.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes Cc: Andrey Vagin Cc: David Hildenbrand (Red Hat) Cc: Jann Horn Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Pedro Falcato Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Cyrill Gorcunov Signed-off-by: Andrew Morton Signed-off-by: Ahmed Elaidy Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/mm/soft-dirty.c | 127 +++++++++++++++++++++++++++++++- 1 file changed, 126 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/mm/soft-dirty.c +++ b/tools/testing/selftests/mm/soft-dirty.c @@ -184,6 +184,130 @@ static void test_mprotect(int pagemap_fd close(test_fd); } +static void test_merge(int pagemap_fd, int pagesize) +{ + char *reserved, *map, *map2; + + /* + * Reserve space for tests: + * + * ---padding to --- + * | avoid adj. | + * v merge v + * |---|---|---|---|---| + * | | 1 | 2 | 3 | | + * |---|---|---|---|---| + */ + reserved = mmap(NULL, 5 * pagesize, PROT_NONE, + MAP_ANON | MAP_PRIVATE, -1, 0); + if (reserved == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + munmap(reserved, 4 * pagesize); + + /* + * Establish initial VMA: + * + * S/D + * |---|---|---|---|---| + * | | 1 | | | | + * |---|---|---|---|---| + */ + map = mmap(&reserved[pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* This will clear VM_SOFTDIRTY too. */ + clear_softdirty(); + + /* + * Now place a new mapping which will be marked VM_SOFTDIRTY. Away from + * map: + * + * - S/D + * |---|---|---|---|---| + * | | 1 | | 2 | | + * |---|---|---|---|---| + */ + map2 = mmap(&reserved[3 * pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* + * Now remap it immediately adjacent to map, if the merge correctly + * propagates VM_SOFTDIRTY, we should then observe the VMA as a whole + * being marked soft-dirty: + * + * merge + * S/D + * |---|-------|---|---| + * | | 1 | | | + * |---|-------|---|---| + */ + map2 = mremap(map2, pagesize, pagesize, MREMAP_FIXED | MREMAP_MAYMOVE, + &reserved[2 * pagesize]); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mremap failed\n"); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-anon soft-dirty after remap merge 1st pg\n", + __func__); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, + "Test %s-anon soft-dirty after remap merge 2nd pg\n", + __func__); + + munmap(map, 2 * pagesize); + + /* + * Now establish another VMA: + * + * S/D + * |---|---|---|---|---| + * | | 1 | | | | + * |---|---|---|---|---| + */ + map = mmap(&reserved[pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* Clear VM_SOFTDIRTY... */ + clear_softdirty(); + /* ...and establish incompatible adjacent VMA: + * + * - S/D + * |---|---|---|---|---| + * | | 1 | 2 | | | + * |---|---|---|---|---| + */ + map2 = mmap(&reserved[2 * pagesize], pagesize, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* + * Now mprotect() VMA 1 so it's compatible with 2 and therefore merges: + * + * merge + * S/D + * |---|-------|---|---| + * | | 1 | | | + * |---|-------|---|---| + */ + if (mprotect(map, pagesize, PROT_READ | PROT_WRITE | PROT_EXEC)) + ksft_exit_fail_msg("mprotect failed\n"); + + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-anon soft-dirty after mprotect merge 1st pg\n", + __func__); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, + "Test %s-anon soft-dirty after mprotect merge 2nd pg\n", + __func__); + + munmap(map, 2 * pagesize); +} + static void test_mprotect_anon(int pagemap_fd, int pagesize) { test_mprotect(pagemap_fd, pagesize, true); @@ -204,7 +328,7 @@ int main(int argc, char **argv) if (!softdirty_supported()) ksft_exit_skip("soft-dirty is not support\n"); - ksft_set_plan(15); + ksft_set_plan(19); pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY); if (pagemap_fd < 0) ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH); @@ -216,6 +340,7 @@ int main(int argc, char **argv) test_hugepage(pagemap_fd, pagesize); test_mprotect_anon(pagemap_fd, pagesize); test_mprotect_file(pagemap_fd, pagesize); + test_merge(pagemap_fd, pagesize); close(pagemap_fd);