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selftests/mm: protection_keys: save/restore nr_hugepages settings

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Save and restore nr_hugepages before changing it during the test.  A test
should not change system wide settings.

Link: https://lkml.kernel.org/r/20240125154608.720072-5-usama.anjum@collabora.com
Fixes: 5f23f6d082 ("x86/pkeys: Add self-tests")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Muhammad Usama Anjum 2024-01-25 20:46:07 +05:00 committed by Andrew Morton
parent 7d695b1c36
commit c23ea61726
1 changed files with 34 additions and 0 deletions
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34
tools/testing/selftests/mm/protection_keys.c
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@ -54,6 +54,7 @@ int test_nr;
u64 shadow_pkey_reg;
int dprint_in_signal;
char dprint_in_signal_buffer[DPRINT_IN_SIGNAL_BUF_SIZE];
char buf[256];
void cat_into_file(char *str, char *file)
{
@ -1744,6 +1745,38 @@ void pkey_setup_shadow(void)
shadow_pkey_reg = __read_pkey_reg();
}
void restore_settings_atexit(void)
{
cat_into_file(buf, "/proc/sys/vm/nr_hugepages");
}
void save_settings(void)
{
int fd;
int err;
if (geteuid())
return;
fd = open("/proc/sys/vm/nr_hugepages", O_RDONLY);
if (fd < 0) {
fprintf(stderr, "error opening\n");
perror("error: ");
exit(__LINE__);
}
/* -1 to guarantee leaving the trailing \0 */
err = read(fd, buf, sizeof(buf)-1);
if (err < 0) {
fprintf(stderr, "error reading\n");
perror("error: ");
exit(__LINE__);
}
atexit(restore_settings_atexit);
close(fd);
}
int main(void)
{
int nr_iterations = 22;
@ -1751,6 +1784,7 @@ int main(void)
srand((unsigned int)time(NULL));
save_settings();
setup_handlers();
printf("has pkeys: %d\n", pkeys_supported);