github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftests/mm: restore enable_soft_offline in hugetlb-soft-offline

Browse Source 
hugetlb-soft-offline toggles /proc/sys/vm/enable_soft_offline between 1
and 0 (test_soft_offline_common(1) then (0)) and leaves it at 0 when it
finishes, silently disabling soft offlining for the whole system after the
run.

Save the original value before the test and restore it from an atexit()
handler, as hugepage_restore_settings_atexit() in hugepage_settings.c
already does.  Use read_num()/write_num() from vm_util instead of
hand-rolled popen()/fopen() helpers.

The restore handler must not call write_num(): on failure it re-enters
exit() through ksft_exit_fail_msg(), which is undefined behavior from
inside an atexit handler.  A non-root run hits it directly - the restore
write fails the same way the write that triggered the exit did.  Restore
with plain open()/write(), best effort.

Link: https://lore.kernel.org/20260825085756.63030-4-husong@kylinos.cn
Signed-off-by: Song Hu <husong@kylinos.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
This commit is contained in:
Song Hu 2026-08-25 16:57:56 +08:00 committed by Andrew Morton
parent fb2f274a79
commit c0f106b518
1 changed files with 28 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
tools/testing/selftests/mm/hugetlb-soft-offline.c
View File

@ -11,6 +11,7 @@
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
@ -23,6 +24,7 @@
#include <sys/types.h>
#include "kselftest.h"
#include "vm_util.h"
#include "hugepage_settings.h"
#ifndef MADV_SOFT_OFFLINE
@ -31,6 +33,8 @@
#define EPREFIX " !!! "
#define ENABLE_SOFT_OFFLINE_PATH "/proc/sys/vm/enable_soft_offline"
static int do_soft_offline(int fd, size_t len, int expect_errno)
{
char *filemap = NULL;
@ -77,26 +81,29 @@ static int do_soft_offline(int fd, size_t len, int expect_errno)
return ret;
}
static int set_enable_soft_offline(int value)
static unsigned long orig_enable_soft_offline = -1UL;
/*
* Runs from an atexit handler, so it must not call anything that
* exits on failure: write_num() would re-enter exit() through
* ksft_exit_fail_msg().
*/
static void restore_enable_soft_offline(void)
{
char cmd[256] = {0};
FILE *cmdfile = NULL;
char buf[24];
int fd, len;
if (value != 0 && value != 1)
return -EINVAL;
if (orig_enable_soft_offline == -1UL)
return;
sprintf(cmd, "echo %d > /proc/sys/vm/enable_soft_offline", value);
cmdfile = popen(cmd, "r");
if (cmdfile)
ksft_print_msg("enable_soft_offline => %d\n", value);
else {
ksft_perror(EPREFIX "failed to set enable_soft_offline");
return errno;
}
pclose(cmdfile);
return 0;
len = snprintf(buf, sizeof(buf), "%lu", orig_enable_soft_offline);
fd = open(ENABLE_SOFT_OFFLINE_PATH, O_WRONLY);
if (fd < 0)
return;
if (write(fd, buf, len) != len)
ksft_print_msg("failed to restore enable_soft_offline: %s\n",
strerror(errno));
close(fd);
}
static int create_hugetlbfs_file(struct statfs *file_stat)
@ -145,10 +152,7 @@ static void test_soft_offline_common(int enable_soft_offline)
hugepagesize_kb = file_stat.f_bsize / 1024;
ksft_print_msg("Hugepagesize is %ldkB\n", hugepagesize_kb);
if (set_enable_soft_offline(enable_soft_offline) != 0) {
close(fd);
ksft_exit_fail_msg("Failed to set enable_soft_offline\n");
}
write_num(ENABLE_SOFT_OFFLINE_PATH, enable_soft_offline);
nr_hugepages_before = hugetlb_nr_default_pages();
@ -192,6 +196,9 @@ int main(int argc, char **argv)
ksft_set_plan(2);
orig_enable_soft_offline = read_num(ENABLE_SOFT_OFFLINE_PATH);
atexit(restore_enable_soft_offline);
test_soft_offline_common(1);
test_soft_offline_common(0);