From db0f1c138f18296e9c1c91619a0517c05ee50f1b Mon Sep 17 00:00:00 2001
From: Brendan Jackman <jackmanb@google.com>
Date: Tue, 11 Mar 2025 13:18:16 +0000
Subject: [PATCH] selftests/mm: print some details when uffd-stress gets bad
 params

So this can be debugged more easily.

Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-5-dec210a658f5@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 tools/testing/selftests/mm/uffd-stress.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index d6b57e5a2e1d7..4ba5bf13a0108 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -457,7 +457,8 @@ int main(int argc, char **argv)
 
 	nr_pages_per_cpu = bytes / page_size / nr_parallel;
 	if (!nr_pages_per_cpu) {
-		_err("invalid MiB");
+		_err("pages_per_cpu = 0, cannot test (%lu / %lu / %lu)",
+			bytes, page_size, nr_parallel);
 		usage();
 	}
 
-- 
2.39.5