From 4050b5b0b60c93160a816d68ea1eb9ae92739a73 Mon Sep 17 00:00:00 2001 From: Hongfu Li Date: Fri, 7 Aug 2026 09:35:55 +0800 Subject: [PATCH] selftests/mm: fix read_file() return value check read_file() returns 0 on open/read failures and never returns negative values. Existing < 0 error checks never trigger, so read failures are silently ignored. Check for zero return to detect read_file() failures. Also fix misleading error message in get_finfo(). The error string incorrectly references read_num when reading uevent files. Link: https://lore.kernel.org/20260807013555.36525-1-hongfu.li@linux.dev Fixes: e0c13f9761df ("khugepaged: add self test") Signed-off-by: Hongfu Li Acked-by: David Hildenbrand (Arm) Cc: Baolin Wang Cc: Barry Song Cc: Dev Jain Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Ryan Roberts Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/khugepaged.c | 4 ++-- tools/testing/selftests/mm/vm_util.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c index 8f221c792a28..d3a53673e1f9 100644 --- a/tools/testing/selftests/mm/khugepaged.c +++ b/tools/testing/selftests/mm/khugepaged.c @@ -141,8 +141,8 @@ static void get_finfo(const char *dir) major(path_stat.st_dev), minor(path_stat.st_dev)) >= sizeof(path)) ksft_exit_fail_msg("%s: Pathname is too long\n", __func__); - if (read_file(path, buf, sizeof(buf)) < 0) - ksft_exit_fail_perror("read_file(read_num)"); + if (!read_file(path, buf, sizeof(buf))) + ksft_exit_fail_perror("read_file(uevent)"); if (strstr(buf, "DEVTYPE=disk")) { /* Found it */ if (snprintf(finfo.dev_queue_read_ahead_path, diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 4fe4a5a610d1..4821a3563036 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -942,7 +942,7 @@ unsigned long read_num(const char *path) { char buf[21]; - if (read_file(path, buf, sizeof(buf)) < 0) + if (!read_file(path, buf, sizeof(buf))) ksft_exit_fail_perror("read_file()"); return strtoul(buf, NULL, 10);