+ selftests-mm-fix-khugepaged_race-build-with-older-glibc.patch added to mm-unstable branch

+ selftests-mm-fix-khugepaged_race-build-with-older-glibc.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: selftests/mm: fix khugepaged_race build with older glibc
has been added to the -mm mm-unstable branch.  Its filename is
     selftests-mm-fix-khugepaged_race-build-with-older-glibc.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-fix-khugepaged_race-build-with-older-glibc.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Zenghui Yu (Huawei)" <zenghui.yu@linux.dev>
Subject: selftests/mm: fix khugepaged_race build with older glibc
Date: Tue, 27 Oct 2026 20:20:13 +0800

glibc versions before 2.37 do not define MADV_COLLAPSE in <sys/mman.h>, so
khugepaged_race fails to build against them (e.g. glibc 2.34):

[root@localhost mm]# make
  CC       khugepaged_race
khugepaged_race.c: In function 'main':
khugepaged_race.c:506:23: error: 'MADV_COLLAPSE' undeclared (first use in this function); did you mean 'MADV_COLD'?
  506 |       hpage_pmd_size, MADV_COLLAPSE);
      |                       ^~~~~~~~~~~~~
      |                       MADV_COLD
khugepaged_race.c:506:23: note: each undeclared identifier is reported only once for each function it appears in
make: *** [../lib.mk:225: /data/code/mm/tools/testing/selftests/mm/khugepaged_race] Error 1

Include <linux/mman.h> to get the UAPI definition of MADV_COLLAPSE.

Link: https://lore.kernel.org/20261027122013.4286-1-zenghui.yu@linux.dev
Fixes: 66c374464438 ("selftests/mm: add khugepaged race harness")
Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
---

 tools/testing/selftests/mm/khugepaged_race.c |    1 +
 1 file changed, 1 insertion(+)

--- a/tools/testing/selftests/mm/khugepaged_race.c~selftests-mm-fix-khugepaged_race-build-with-older-glibc
+++ a/tools/testing/selftests/mm/khugepaged_race.c
@@ -8,6 +8,7 @@
 #define _GNU_SOURCE
 #include <errno.h>
 #include <fcntl.h>
+#include <linux/mman.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
_

Patches currently in -mm which might be from zenghui.yu@linux.dev are

mm-page_alloc-mark-pages-freed-by-__free_pages_core-as-not-tagged.patch
selftests-mm-fix-khugepaged_race-build-with-older-glibc.patch