From: David Hildenbrand <david@redhat.com> stable inclusion from stable-v6.6.8 commit ca3ebcf2c448f04ae144ddb19ad68b4cab6fcad2 bugzilla: https://gitee.com/openeuler/kernel/issues/I99K53 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit a6fcd57cf2df409d35e9225b8dbad6f937b28df0 ] Doing a ksft_print_msg() before the ksft_print_header() seems to confuse the ksft framework in a strange way: running the test on the cmdline results in the expected output. But piping the output somewhere else, results in some odd output, whereby we repeatedly get the same info printed: # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled TAP version 13 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled TAP version 13 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page ok 1 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped out base page # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled Doing the ksft_print_header() first seems to resolve that and gives us the output we expect: TAP version 13 # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page ok 1 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped out base page ok 2 No leak from parent into child # [RUN] Basic COW after fork() ... with THP ok 3 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped-out THP ok 4 No leak from parent into child # [RUN] Basic COW after fork() ... with PTE-mapped THP ok 5 No leak from parent into child Link: https://lkml.kernel.org/r/20231206103558.38040-1-david@redhat.com Fixes: f4b5fd6946e2 ("selftests/vm: anon_cow: THP tests") Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Nico Pache <npache@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> --- tools/testing/selftests/mm/cow.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c index ace94bfb532d..363bf5f801be 100644 --- a/tools/testing/selftests/mm/cow.c +++ b/tools/testing/selftests/mm/cow.c @@ -1738,6 +1738,8 @@ int main(int argc, char **argv) int err; struct thp_settings default_settings; + ksft_print_header(); + pagesize = getpagesize(); pmdsize = read_pmd_pagesize(); if (pmdsize) { @@ -1755,7 +1757,6 @@ int main(int argc, char **argv) ARRAY_SIZE(hugetlbsizes)); detect_huge_zeropage(); - ksft_print_header(); ksft_set_plan(ARRAY_SIZE(anon_test_cases) * tests_per_anon_test_case() + ARRAY_SIZE(anon_thp_test_cases) * tests_per_anon_thp_test_case() + ARRAY_SIZE(non_anon_test_cases) * tests_per_non_anon_test_case()); -- 2.25.1