From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9232E2DC348 for ; Mon, 15 Sep 2025 23:45:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757979906; cv=none; b=KTi+i4i+NKJ569jp2oJsatkjAXsvYElrIuQ7m1FmXms2FzM0JdIi2zCrY/2UB5x7eEczh9og5aSVrWlMRgjrqZNKiYbD6XkD5Q/zRrZWZnyX3zivVDgJbGITa4EYGhLMc1IxUh5mG25agCVE2P1cBODEOmnU9912MR0xC7EvZ1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757979906; c=relaxed/simple; bh=MRIow+HN1oD1310t0rESYZD8em9OKe8AtovAEgem8HE=; h=Date:To:From:Subject:Message-Id; b=Y5wnnum11jqxHUtjcKb8dfbUU9QUHg8j37DU1a1Bv5dOoJb5Kbj/OE81Yfrkq0++WJEjDqIWOJgMi/MNlLM8iBafk6ZU/rPrYXCn6rDfOwzA6XD8kkiRckULjEucvYJwnL4GJ/Jq/ReHV5aY49JPN+4TreGrk54SFKnEfKjbaY4= 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=M+yLDak4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="M+yLDak4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BE00C4CEF1; Mon, 15 Sep 2025 23:45:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1757979906; bh=MRIow+HN1oD1310t0rESYZD8em9OKe8AtovAEgem8HE=; h=Date:To:From:Subject:From; b=M+yLDak4mPWh9SpJR82G8R0XHp9OXdNeeAx++/g3vlv7F7JlQkX+8++q5+22eFhmh CZBmkeqvS+SO6kaptJJMFCzZyxHAlQRXMDCDtwfJYqcdLwrLlOS7KvJIAeofzcoAGu Plb/od6ukgWZ0vsQZ2bwN0UvUxILwwmSyddxhf7c= Date: Mon, 15 Sep 2025 16:45:05 -0700 To: mm-commits@vger.kernel.org,xu.xin16@zte.com.cn,ritesh.list@gmail.com,richard.weiyang@gmail.com,david@redhat.com,chengming.zhou@linux.dev,aboorvad@linux.ibm.com,donettom@linux.ibm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-added-fork-inheritance-test-for-ksm_merging_pages-counter.patch added to mm-new branch Message-Id: <20250915234506.3BE00C4CEF1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/mm: added fork inheritance test for ksm_merging_pages counter has been added to the -mm mm-new branch. Its filename is selftests-mm-added-fork-inheritance-test-for-ksm_merging_pages-counter.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-added-fork-inheritance-test-for-ksm_merging_pages-counter.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Donet Tom Subject: selftests/mm: added fork inheritance test for ksm_merging_pages counter Date: Mon, 15 Sep 2025 20:33:05 +0530 Add a new selftest to verify whether the `ksm_merging_pages` counter in `mm_struct` is not inherited by a child process after fork. This helps ensure correctness of KSM accounting across process creation. Link: https://lkml.kernel.org/r/f07c901d4b6b1d1c15a8c1bbd324367d6135d0a3.1757946863.git.donettom@linux.ibm.com Signed-off-by: Donet Tom Cc: Aboorva Devarajan Cc: Chengming Zhou Cc: David Hildenbrand Cc: "Ritesh Harjani (IBM)" Cc: Wei Yang Cc: xu xin Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/ksm_functional_tests.c | 42 +++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/mm/ksm_functional_tests.c~selftests-mm-added-fork-inheritance-test-for-ksm_merging_pages-counter +++ a/tools/testing/selftests/mm/ksm_functional_tests.c @@ -602,6 +602,45 @@ unmap: munmap(map, size); } +static void test_fork_ksm_merging_page_count(void) +{ + const unsigned int size = 2 * MiB; + char *map; + pid_t child_pid; + int status; + + ksft_print_msg("[RUN] %s\n", __func__); + + map = mmap_and_merge_range(0xcf, size, PROT_READ | PROT_WRITE, KSM_MERGE_MADVISE); + if (map == MAP_FAILED) + return; + + child_pid = fork(); + if (!child_pid) { + init_global_file_handles(); + exit(ksm_get_self_merging_pages()); + } else if (child_pid < 0) { + ksft_test_result_fail("fork() failed\n"); + return; + } + + if (waitpid(child_pid, &status, 0) < 0) { + ksft_test_result_fail("waitpid() failed\n"); + return; + } + + status = WEXITSTATUS(status); + if (status) { + ksft_test_result_fail("ksm_merging_page in child: %d\n", status); + return; + } + + ksft_test_result_pass("ksm_merging_pages is not inherited after fork\n"); + + ksm_stop(); + munmap(map, size); +} + static void init_global_file_handles(void) { mem_fd = open("/proc/self/mem", O_RDWR); @@ -620,7 +659,7 @@ static void init_global_file_handles(voi int main(int argc, char **argv) { - unsigned int tests = 8; + unsigned int tests = 9; int err; if (argc > 1 && !strcmp(argv[1], FORK_EXEC_CHILD_PRG_NAME)) { @@ -652,6 +691,7 @@ int main(int argc, char **argv) test_prctl_fork(); test_prctl_fork_exec(); test_prctl_unmerge(); + test_fork_ksm_merging_page_count(); err = ksft_get_fail_cnt(); if (err) _ Patches currently in -mm which might be from donettom@linux.ibm.com are mm-ksm-fix-incorrect-ksm-counter-handling-in-mm_struct-during-fork.patch selftests-mm-added-fork-inheritance-test-for-ksm_merging_pages-counter.patch selftests-mm-added-fork-test-to-verify-global-ksm_zero_pages-counter-behavior.patch