The patch titled
Subject: selftests: mm: restore settings from only parent process
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
selftests-mm-restore-settings-from-only-parent-process.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-restore-settings-from-only-parent-process.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Subject: selftests: mm: restore settings from only parent process
Date: Thu, 14 Mar 2024 14:40:45 +0500
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@xxxxxxxxxxxxx
Fixes: c23ea61726d5 ("selftests/mm: protection_keys: save/restore nr_hugepages settings")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Tested-by: Joey Gouly <joey.gouly@xxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/protection_keys.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/mm/protection_keys.c~selftests-mm-restore-settings-from-only-parent-process
+++ a/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);
}
_
Patches currently in -mm which might be from usama.anjum@xxxxxxxxxxxxx are
selftests-mm-restore-settings-from-only-parent-process.patch
