Re: [PATCH] tests/qtest: Poll on waitpid() for a while before sending SIGKILL

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Jan 11, 2023 at 05:30:18PM -0500, Stefan Berger wrote:
> To prevent getting stuck on waitpid() in case the target process does
> not terminate on SIGTERM, poll on waitpid() for 10s and if the target
> process has not changed state until then send a SIGKILL to it.
> 
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
>  tests/qtest/libqtest.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)

Since this is a test suite and we know our CI system gets very
heavily loaded, I think we should wait more than 10 secs, to
ensure QEMU has time to flush pending I/O in particular which
is most likely to delay things. If you bump the time to 30 secs
then

  Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

> 
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index 2fbc3b88f3..362b1f724f 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -202,8 +202,24 @@ void qtest_wait_qemu(QTestState *s)
>  {
>  #ifndef _WIN32
>      pid_t pid;
> +    uint64_t end;
> +
> +    /* poll for 10s until sending SIGKILL */
> +    end = g_get_monotonic_time() + 10 * G_TIME_SPAN_SECOND;
> +
> +    do {
> +        pid = waitpid(s->qemu_pid, &s->wstatus, WNOHANG);
> +        if (pid != 0) {
> +            break;
> +        }
> +        g_usleep(100 * 1000);
> +    } while (g_get_monotonic_time() < end);
> +
> +    if (pid == 0) {
> +        kill(s->qemu_pid, SIGKILL);
> +        TFR(pid = waitpid(s->qemu_pid, &s->wstatus, 0));
> +    }
>  
> -    TFR(pid = waitpid(s->qemu_pid, &s->wstatus, 0));
>      assert(pid == s->qemu_pid);
>  #else
>      DWORD ret;
> -- 
> 2.39.0
> 

With regards,
Daniel
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