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SubjectRe: [PATCH 1/2] kselftest: signal all child processes
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On 12/2/21 8:05 PM, lizhijian@fujitsu.com wrote:
> kindly ping
>
>
> On 29/10/2021 16:31, Christian Brauner wrote:
>> On Fri, Oct 29, 2021 at 10:45:27AM +0800, Li Zhijian wrote:
>>> We have some many cases that will create child process as well, such as
>>> pidfd_wait. Previously, we will signal/kill the parent process when it
>>> is time out, but this signal will not be sent to its child process. In
>>> such case, if child process doesn't terminate itself, ksefltest framework
>>> will hang forever.
>>>
>>> below ps tree show the situation when ksefltest is blocking:
>>> root 1172 0.0 0.0 5996 2500 ? S 07:03 0:00 \_ /bin/bash /lkp/lkp/src/tests/kernel-selftests
>>> root 1216 0.0 0.0 4392 1976 ? S 07:03 0:00 \_ make run_tests -C pidfd
>>> root 1218 0.0 0.0 2396 1652 ? S 07:03 0:00 \_ /bin/sh -c BASE_DIR="/usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests"; . /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/runner.sh; if [ "X" != "X" ]; then per_test_logging=1; fi; run_many /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_fdinfo_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_open_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_poll_test /usr/src/perf_selftests-x86_64-rhel-8.
>>> root 12491 0.0 0.0 2396 132 ? S 07:03 0:00 \_ /bin/sh -c BASE_DIR="/usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests"; . /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/runner.sh; if [ "X" != "X" ]; then per_test_logging=1; fi; run_many /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_fdinfo_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_open_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_poll_test /usr/src/perf_selftests-x86_64-rhe
>>> root 12492 0.0 0.0 2396 132 ? S 07:03 0:00 \_ /bin/sh -c BASE_DIR="/usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests"; . /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/runner.sh; if [ "X" != "X" ]; then per_test_logging=1; fi; run_many /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_fdinfo_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_open_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_poll_test /usr/src/perf_selftests-x86_64
>>> root 12493 0.0 0.0 2396 132 ? S 07:03 0:00 \_ /bin/sh -c BASE_DIR="/usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests"; . /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/runner.sh; if [ "X" != "X" ]; then per_test_logging=1; fi; run_many /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_fdinfo_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_open_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_poll_test /usr/src/perf_selftests-x8
>>> root 12496 0.0 0.0 2396 132 ? S 07:03 0:00 \_ /bin/sh -c BASE_DIR="/usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests"; . /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/runner.sh; if [ "X" != "X" ]; then per_test_logging=1; fi; run_many /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_fdinfo_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_open_test /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/pidfd/pidfd_poll_test /usr/src/perf_selftest
>>> root 12498 0.0 0.0 10564 6116 ? S 07:03 0:00 \_ perl /usr/src/perf_selftests-x86_64-rhel-8.3-kselftests-519d81956ee277b4419c723adfb154603c2565ba/tools/testing/selftests/kselftest/prefix.pl
>>> root 12503 0.0 0.0 2452 112 ? T 07:03 0:00 ./pidfd_wait
>>> root 12621 0.0 0.0 2372 1600 ? SLs 07:04 0:00 /usr/sbin/watchdog
>>> root 19438 0.0 0.0 992 60 ? Ss 07:39 0:00 /lkp/lkp/src/bin/event/wakeup activate-monitor
>>>
>>> Here we group all its child processes so that kill() can signal all of
>>> them in timeout.
>>>
>>> CC: Kees Cook <keescook@chromium.org>
>>> CC: Andy Lutomirski <luto@amacapital.net>
>>> CC: Will Drewry <wad@chromium.org>
>>> CC: Shuah Khan <shuah@kernel.org>
>>> CC: Christian Brauner <christian@brauner.io>
>>> CC: Philip Li <philip.li@intel.com>
>>> Suggested-by: yang xu <xuyang2018.jy@cn.fujitsu.com>
>>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>>> ---
>> Seems sensible. Is it guaranteed that t->pid is neither 0 nor 1? If not
>> then maybe sanity check t->pid at least for not being 1 as negating that
>> would mean "signal everything that you have permission to signal". :)
>>
>> Otherwise,
>> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
>>
>>> tools/testing/selftests/kselftest_harness.h | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
>>> index ae0f0f33b2a6..c7251396e7ee 100644
>>> --- a/tools/testing/selftests/kselftest_harness.h
>>> +++ b/tools/testing/selftests/kselftest_harness.h
>>> @@ -875,7 +875,8 @@ static void __timeout_handler(int sig, siginfo_t *info, void *ucontext)
>>> }
>>>
>>> t->timed_out = true;
>>> - kill(t->pid, SIGKILL);
>>> + // signal process group
>>> + kill(-(t->pid), SIGKILL);
>>> }
>>>
>>> void __wait_for_test(struct __test_metadata *t)
>>> @@ -985,6 +986,7 @@ void __run_test(struct __fixture_metadata *f,
>>> ksft_print_msg("ERROR SPAWNING TEST CHILD\n");
>>> t->passed = 0;
>>> } else if (t->pid == 0) {
>>> + setpgrp();
>>> t->fn(t, variant);
>>> if (t->skip)
>>> _exit(255);
>>> --
>>> 2.33.0
>>>
>>>
>>>
>>
>

Kees,

Will you be able to take a look at this fix? This is in the kselftest_harness

thanks,
-- Shuah
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