get_finfo() calls stat() to get metadata about the target directory, but never checks the return value. On failure, stat() returns -1 and leaves path_stat unmodified, so path_stat.st_mode may contain uninitialized stack data.
The code then checks S_ISDIR(path_stat.st_mode) against this potentially garbage value. This can produce a misleading "Not a directory" error when the real problem is a nonexistent or inaccessible path, or, in the worst case, the check could pass by chance on garbage data and let the function continue using an invalid path_stat for the rest of its logic. Check the return value and fail with a clear error message if stat() fails, matching the error-handling style already used for statfs() and read_file() later in the same function. Signed-off-by: Anshuman <[email protected]> --- tools/testing/selftests/mm/khugepaged.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c index 10e8dedcb..2240a9b4f 100644 --- a/tools/testing/selftests/mm/khugepaged.c +++ b/tools/testing/selftests/mm/khugepaged.c @@ -121,7 +121,8 @@ static void get_finfo(const char *dir) char *str, *end; finfo.dir = dir; - stat(finfo.dir, &path_stat); + if (stat(finfo.dir, &path_stat)) + ksft_exit_fail_perror("stat()"); if (!S_ISDIR(path_stat.st_mode)) ksft_exit_fail_msg("%s: Not a directory (%s)\n", __func__, finfo.dir); if (snprintf(finfo.path, sizeof(finfo.path), "%s/" TEST_FILE, -- 2.55.0
