[PATCH v3 10/13] selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero

Sayali Patil
2026-03-27T07:18:08Z

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.

Fixes: db0f1c138f18 ("selftests/mm: print some details when uffd-stress gets bad params")
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
---
tools/testing/selftests/mm/uffd-stress.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 700fbaa18d44..b8f22ea859a6 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -491,9 +491,9 @@ 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_print_msg("pages_per_cpu = 0, cannot test (%lu / %lu / %lu)\n",
+ bytes, gopts->page_size, gopts->nr_parallel);
+ return KSFT_SKIP;
}

bounces = atoi(argv[3]);
--
2.52.0