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selftests/mm:fix test_prctl_fork_exec return failure

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After calling fork() in test_prctl_fork_exec(), the global variable
ksm_full_scans_fd is initialized to 0 in the child process upon entering
the main function of ./ksm_functional_tests.

In the function call chain test_child_ksm() -> __mmap_and_merge_range ->
ksm_merge-> ksm_get_full_scans, start_scans = ksm_get_full_scans() will
return an error.  Therefore, the value of ksm_full_scans_fd needs to be
initialized before calling test_child_ksm in the child process.

Link: https://lkml.kernel.org/r/20240617052934.5834-1-shechenglong001@gmail.com
Signed-off-by: aigourensheng <shechenglong001@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
aigourensheng 2024-06-17 01:29:34 -04:00 committed by Andrew Morton
parent ff202303c3
commit 8b8546d298
1 changed files with 24 additions and 18 deletions
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42
tools/testing/selftests/mm/ksm_functional_tests.c
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@ -656,24 +656,8 @@ static void test_prot_none(void)
munmap(map, size);
}
int main(int argc, char **argv)
static void init_global_file_handles(void)
{
unsigned int tests = 8;
int err;
if (argc > 1 && !strcmp(argv[1], FORK_EXEC_CHILD_PRG_NAME)) {
exit(test_child_ksm());
}
#ifdef __NR_userfaultfd
tests++;
#endif
ksft_print_header();
ksft_set_plan(tests);
pagesize = getpagesize();
mem_fd = open("/proc/self/mem", O_RDWR);
if (mem_fd < 0)
ksft_exit_fail_msg("opening /proc/self/mem failed\n");
@ -688,8 +672,30 @@ int main(int argc, char **argv)
ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n");
proc_self_ksm_stat_fd = open("/proc/self/ksm_stat", O_RDONLY);
proc_self_ksm_merging_pages_fd = open("/proc/self/ksm_merging_pages",
O_RDONLY);
O_RDONLY);
ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR);
}
int main(int argc, char **argv)
{
unsigned int tests = 8;
int err;
if (argc > 1 && !strcmp(argv[1], FORK_EXEC_CHILD_PRG_NAME)) {
init_global_file_handles();
exit(test_child_ksm());
}
#ifdef __NR_userfaultfd
tests++;
#endif
ksft_print_header();
ksft_set_plan(tests);
pagesize = getpagesize();
init_global_file_handles();
test_unmerge();
test_unmerge_zero_pages();