diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c
index e198facf78bb..5f278913c4d7 100644
--- a/tools/testing/selftests/mm/soft-dirty.c
+++ b/tools/testing/selftests/mm/soft-dirty.c
@@ -152,7 +152,8 @@ static void test_mprotect(int pagemap_fd, int pagesize, bool anon)
 			return;
 		}
 		unlink(fname);
-		ftruncate(test_fd, pagesize);
+		if (ftruncate(test_fd, pagesize) != 0)
+			ksft_exit_fail_msg("ftruncate failed\n");
 		map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
 			   MAP_SHARED, test_fd, 0);
 		if (map == MAP_FAILED)