[PATCH] selftests/mm: ksm_tests: skip when not run as root

[Sun Jian <sun.jian.kdev@gmail.com>]

ksm_tests writes KSM sysfs knobs under /sys/kernel/mm/ksm, which requires
root privileges. When run unprivileged, it fails with permission errors
and reports FAIL, which is misleading.

Skip the test early when not run as root to avoid false failures.

Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
---
 tools/testing/selftests/mm/ksm_tests.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
index a0b48b839d54..c22cd9c61711 100644
--- a/tools/testing/selftests/mm/ksm_tests.c
+++ b/tools/testing/selftests/mm/ksm_tests.c
@@ -766,6 +766,11 @@ int main(int argc, char *argv[])
 	bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
 	long size_MB = 0;
 
+	if (geteuid() != 0) {
+		printf("# SKIP ksm_tests requires root privileges\n");
+		return KSFT_SKIP;
+	}
+
 	while ((opt = getopt(argc, argv, "dha:p:l:z:m:s:t:MUZNPCHD")) != -1) {
 		switch (opt) {
 		case 'a':
-- 
2.43.0