The patch titled
Subject: selftests/mm:fix test_prctl_fork_exec return failure
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
selftests-mm-fix-test_prctl_fork_exec-return-failure.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-fix-test_prctl_fork_exec-return-failure.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: aigourensheng <shechenglong001@xxxxxxxxx>
Subject: selftests/mm:fix test_prctl_fork_exec return failure
Date: Mon, 17 Jun 2024 01:29:34 -0400
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@xxxxxxxxx
Signed-off-by: aigourensheng <shechenglong001@xxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/ksm_functional_tests.c | 38 ++++++------
1 file changed, 22 insertions(+), 16 deletions(-)
--- a/tools/testing/selftests/mm/ksm_functional_tests.c~selftests-mm-fix-test_prctl_fork_exec-return-failure
+++ a/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -656,12 +656,33 @@ unmap:
munmap(map, size);
}
+static void init_global_file_handles(void)
+{
+ mem_fd = open("/proc/self/mem", O_RDWR);
+ if (mem_fd < 0)
+ ksft_exit_fail_msg("opening /proc/self/mem failed\n");
+ ksm_fd = open("/sys/kernel/mm/ksm/run", O_RDWR);
+ if (ksm_fd < 0)
+ ksft_exit_skip("open(\"/sys/kernel/mm/ksm/run\") failed\n");
+ ksm_full_scans_fd = open("/sys/kernel/mm/ksm/full_scans", O_RDONLY);
+ if (ksm_full_scans_fd < 0)
+ ksft_exit_skip("open(\"/sys/kernel/mm/ksm/full_scans\") failed\n");
+ pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
+ if (pagemap_fd < 0)
+ 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);
+ 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());
}
@@ -674,22 +695,7 @@ int main(int argc, char **argv)
pagesize = getpagesize();
- mem_fd = open("/proc/self/mem", O_RDWR);
- if (mem_fd < 0)
- ksft_exit_fail_msg("opening /proc/self/mem failed\n");
- ksm_fd = open("/sys/kernel/mm/ksm/run", O_RDWR);
- if (ksm_fd < 0)
- ksft_exit_skip("open(\"/sys/kernel/mm/ksm/run\") failed\n");
- ksm_full_scans_fd = open("/sys/kernel/mm/ksm/full_scans", O_RDONLY);
- if (ksm_full_scans_fd < 0)
- ksft_exit_skip("open(\"/sys/kernel/mm/ksm/full_scans\") failed\n");
- pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
- if (pagemap_fd < 0)
- 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);
- ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR);
+ init_global_file_handles();
test_unmerge();
test_unmerge_zero_pages();
_
Patches currently in -mm which might be from shechenglong001@xxxxxxxxx are
selftests-mm-fix-test_prctl_fork_exec-return-failure.patch
