From f3bd00507f226a419125df6064632bcbd47d8e70 Mon Sep 17 00:00:00 2001 From: Sayali Patil Date: Thu, 21 May 2026 12:17:51 +0530 Subject: [PATCH] selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero uffd-stress currently fails when the computed nr_pages_per_cpu evaluates to zero: nr_pages_per_cpu = bytes / page_size / nr_parallel This can occur on systems with large hugepage sizes (e.g. 1GB) and a high number of CPUs, where the total allocated memory is sufficient overall but not enough to provide at least one page per cpu. In such cases, the failure is due to insufficient test resources rather than incorrect kernel behaviour. Update the test to treat this condition as a test skip instead of reporting an error. [sayalip@linux.ibm.com: use ksft_exit_skip() instead of KSFT_SKIP] Link: https://lore.kernel.org/88202b56-1dc5-43e2-9d1f-a0823a9531f0@linux.ibm.com Link: https://lore.kernel.org/0707e9a0f1b3dd904c4a069b91db317f9c160faa.1779296493.git.sayalip@linux.ibm.com Fixes: db0f1c138f18 ("selftests/mm: print some details when uffd-stress gets bad params") Signed-off-by: Sayali Patil Acked-by: Zi Yan Acked-by: David Hildenbrand (Arm) Tested-by: Venkat Rao Bagalkote Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/uffd-stress.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index 43cc79590136..3401dd6028f0 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -489,9 +489,8 @@ int main(int argc, char **argv) gopts->nr_pages_per_cpu = bytes / gopts->page_size / gopts->nr_parallel; if (!gopts->nr_pages_per_cpu) { - _err("pages_per_cpu = 0, cannot test (%lu / %lu / %lu)", - bytes, gopts->page_size, gopts->nr_parallel); - usage(); + ksft_exit_skip("pages_per_cpu = 0, cannot test (%zu / %lu / %lu)\n", + bytes, gopts->page_size, gopts->nr_parallel); } bounces = atoi(argv[3]);