From c52eb6db7b7dd8b4b338b16c5c37df22a6b08fdf Mon Sep 17 00:00:00 2001 From: Muhammad Usama Anjum Date: Thu, 14 Mar 2024 14:40:45 +0500 Subject: selftests: mm: restore settings from only parent process The atexit() is called from parent process as well as forked processes. Hence the child restores the settings at exit while the parent is still executing. Fix this by checking pid of atexit() calling process and only restore THP number from parent process. Link: https://lkml.kernel.org/r/20240314094045.157149-1-usama.anjum@collabora.com Fixes: c23ea61726d5 ("selftests/mm: protection_keys: save/restore nr_hugepages settings") Signed-off-by: Muhammad Usama Anjum Tested-by: Joey Gouly Cc: Shuah Khan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/protection_keys.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/protection_keys.c b/tools/testing/selftests/mm/protection_keys.c index f822ae31af22e2..374a308174d2ba 100644 --- a/tools/testing/selftests/mm/protection_keys.c +++ b/tools/testing/selftests/mm/protection_keys.c @@ -1745,9 +1745,12 @@ void pkey_setup_shadow(void) shadow_pkey_reg = __read_pkey_reg(); } +pid_t parent_pid; + void restore_settings_atexit(void) { - cat_into_file(buf, "/proc/sys/vm/nr_hugepages"); + if (parent_pid == getpid()) + cat_into_file(buf, "/proc/sys/vm/nr_hugepages"); } void save_settings(void) @@ -1773,6 +1776,7 @@ void save_settings(void) exit(__LINE__); } + parent_pid = getpid(); atexit(restore_settings_atexit); close(fd); } -- cgit 1.2.3-korg