+ selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file.patch added to mm-new branch

+ selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: selftests/mm: skip split_huge_page_test without the split_huge_pages file
has been added to the -mm mm-new branch.  Its filename is
     selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file.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.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: Sasha Levin <sashal@kernel.org>
Subject: selftests/mm: skip split_huge_page_test without the split_huge_pages file
Date: Wed,  4 Nov 2026 22:02:42 -0500

Every case in split_huge_page_test goes through
/sys/kernel/debug/split_huge_pages.  When that file does not exist,
because debugfs is not mounted or the kernel has no CONFIG_DEBUG_FS, the
first write bails out of the whole test and it is reported as a failure:

  Bail out! write_file(/sys/kernel/debug/split_huge_pages): No such file or directory

Skip the test in that case.

Link: https://lore.kernel.org/20261105030242.1241448-1-sashal@kernel.org
Fixes: fa6c02315f74 ("mm: huge_memory: a new debugfs interface for splitting THP tests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
---

 tools/testing/selftests/mm/split_huge_page_test.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/testing/selftests/mm/split_huge_page_test.c~selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file
+++ a/tools/testing/selftests/mm/split_huge_page_test.c
@@ -610,6 +610,9 @@ int main(int argc, char **argv)
 	if (!thp_is_enabled())
 		ksft_exit_skip("Transparent Hugepages not available\n");
 
+	if (access(SPLIT_DEBUGFS, W_OK))
+		ksft_exit_skip("%s: %s\n", SPLIT_DEBUGFS, strerror(errno));
+
 	if (argc > 1)
 		optional_xfs_path = argv[1];
 
_

Patches currently in -mm which might be from sashal@kernel.org are

selftests-proc-cast-the-procmap_query-address-through-uintptr_t.patch
selftests-mm-fix-pointer-width-warnings-on-32-bit-architectures.patch
selftests-mm-uffd-wp-mremap-keep-the-thp-sizes-in-unsigned-long.patch
selftests-mm-skip-split_huge_page_test-without-the-split_huge_pages-file.patch
selftests-proc-search-the-kernel-headers-before-the-tools-copies.patch
selftests-prctl-select-the-tests-by-arch-alone.patch