Re: [PATCH 41/51] tests/qtest: migration-test: Kill "to" after migration is canceled

[Bin Meng]

On Thu, Sep 1, 2022 at 7:35 PM Marc-André Lureau
<marcandre.lureau@gmail.com> wrote:
>
> Hi
>
> On Wed, Aug 24, 2022 at 10:56 PM Dr. David Alan Gilbert <dgilbert@redhat.com> 
> wrote:
>>
>> * Bin Meng (bmeng.cn@gmail.com) wrote:
>> > From: Xuzhou Cheng <xuzhou.cheng@windriver.com>
>> >
>> > Make sure QEMU process "to" is killed before launching another target
>> > for migration in the test_multifd_tcp_cancel case.
>> >
>> > Signed-off-by: Xuzhou Cheng <xuzhou.cheng@windriver.com>
>> > Signed-off-by: Bin Meng <bin.meng@windriver.com>
>> > ---
>> >
>> >  tests/qtest/migration-test.c | 4 ++++
>> >  1 file changed, 4 insertions(+)
>> >
>> > diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
>> > index 125d48d855..18ec079abf 100644
>> > --- a/tests/qtest/migration-test.c
>> > +++ b/tests/qtest/migration-test.c
>> > @@ -2132,6 +2132,10 @@ static void test_multifd_tcp_cancel(void)
>> >      wait_for_migration_pass(from);
>> >
>> >      migrate_cancel(from);
>> > +    /* Make sure QEMU process "to" is killed */
>> > +    if (qtest_probe_child(to)) {
>> > +        qtest_kill_qemu(to);
>> > +    }
>>
>> I'm not sure that's safe - what happens if the qemu exits between the
>> probe and kill?
>

Umm, indeed there will be an issue if qemu exists between the probe and kill.

I will change to a busy wait in v2.

>
> It looks safe to me, qtest_probe_child() resets the qemu_pid if it already 
> exited. Otherwise, there is a process/handle waiting for waitpid/CloseHandle 
> done in qtest_kill_qemu().
>
> We are missing a CloseHandle() in qtest_probe_child() though, I'll send a 
> patch.
>
> so lgtm,
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Regards,
Bin