From 4e1fbffb3333626682a011db7c4b4e9e40ba96d4 Mon Sep 17 00:00:00 2001 From: Sayali Patil Date: Wed, 8 Jul 2026 12:29:07 +0530 Subject: [PATCH] selftests/mm: fix ternary operator precedence in ksm_tests The KSM selftest uses conditional expressions to skip accesses to merge_across_nodes on systems without NUMA support. However, the ternary operator is combined with logical OR without parentheses: a || numa_available() ? 0 : b || c Due to operator precedence rules, this is parsed as: (a || numa_available()) ? 0 : (b || c) instead of the intended: a || (numa_available() ? 0 : b) || c Add parentheses around the conditional expressions to ensure the correct evaluation order. Link: https://lore.kernel.org/ce859430287ed2642848c933a90eb9a69da361f0.1783446924.git.sayalip@linux.ibm.com Fixes: 9aa1af954db0 ("selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests") Signed-off-by: Sayali Patil Acked-by: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/ksm_tests.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c index 2ebbb544c671..5fd7792a0d47 100644 --- a/tools/testing/selftests/mm/ksm_tests.c +++ b/tools/testing/selftests/mm/ksm_tests.c @@ -288,8 +288,8 @@ static bool assert_ksm_pages_count(long dupl_page_count) static int ksm_save_def(struct ksm_sysfs *ksm_sysfs) { if (ksm_read_sysfs(KSM_FP("max_page_sharing"), &ksm_sysfs->max_page_sharing) || - numa_available() ? 0 : - ksm_read_sysfs(KSM_FP("merge_across_nodes"), &ksm_sysfs->merge_across_nodes) || + (numa_available() ? 0 : + ksm_read_sysfs(KSM_FP("merge_across_nodes"), &ksm_sysfs->merge_across_nodes)) || ksm_read_sysfs(KSM_FP("sleep_millisecs"), &ksm_sysfs->sleep_millisecs) || ksm_read_sysfs(KSM_FP("pages_to_scan"), &ksm_sysfs->pages_to_scan) || ksm_read_sysfs(KSM_FP("run"), &ksm_sysfs->run) || @@ -304,8 +304,8 @@ static int ksm_save_def(struct ksm_sysfs *ksm_sysfs) static int ksm_restore(struct ksm_sysfs *ksm_sysfs) { if (ksm_write_sysfs(KSM_FP("max_page_sharing"), ksm_sysfs->max_page_sharing) || - numa_available() ? 0 : - ksm_write_sysfs(KSM_FP("merge_across_nodes"), ksm_sysfs->merge_across_nodes) || + (numa_available() ? 0 : + ksm_write_sysfs(KSM_FP("merge_across_nodes"), ksm_sysfs->merge_across_nodes)) || ksm_write_sysfs(KSM_FP("pages_to_scan"), ksm_sysfs->pages_to_scan) || ksm_write_sysfs(KSM_FP("run"), ksm_sysfs->run) || ksm_write_sysfs(KSM_FP("sleep_millisecs"), ksm_sysfs->sleep_millisecs) || @@ -846,8 +846,8 @@ int main(int argc, char *argv[]) if (ksm_write_sysfs(KSM_FP("run"), 2) || ksm_write_sysfs(KSM_FP("sleep_millisecs"), 0) || - numa_available() ? 0 : - ksm_write_sysfs(KSM_FP("merge_across_nodes"), 1) || + (numa_available() ? 0 : + ksm_write_sysfs(KSM_FP("merge_across_nodes"), 1)) || ksm_write_sysfs(KSM_FP("pages_to_scan"), page_count)) ksft_exit_fail_msg("Cannot set up KSM tunables\n");