Re: [PATCH] system/qtest.c: Allow for multiple CHR_EVENT_CLOSED events

[Fabiano Rosas <farosas@suse.de>]

Peter Maydell <peter.maydell@linaro.org> writes:

> Ping for code review?
>
> thanks
> -- PMM
>
> On Fri, 7 Nov 2025 at 17:43, Peter Maydell <peter.maydell@linaro.org> wrote:
>>
>> In the qtest_event() QEMUChrEvent handler, we create a timer
>> and log OPENED on CHR_EVENT_OPENED, and we destroy the timer and
>> log CLOSED on CHR_EVENT_CLOSED. However, the chardev subsystem
>> can send us more than one CHR_EVENT_CLOSED if we're reading from
>> a file chardev:
>>  * the first one happens when we read the last data from the file
>>  * the second one happens when the user hits ^C to exit QEMU
>>    and the chardev is finalized: char_fd_finalize()
>>
>> This causes us to call g_timer_elapsed() with a NULL timer
>> (which glib complains about) and print an extra CLOSED log line
>> with a zero timestamp:
>>
>> [I +0.063829] CLOSED
>> qemu-system-aarch64: GLib: g_timer_elapsed: assertion 'timer != NULL' failed
>> [I +0.000000] CLOSED
>>
>> Avoid this by ignoring a CHR_EVENT_CLOSED if we have already
>> processed one.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> ---
>>  system/qtest.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/system/qtest.c b/system/qtest.c
>> index baef06d4d1b..67e2385f4b0 100644
>> --- a/system/qtest.c
>> +++ b/system/qtest.c
>> @@ -815,6 +815,10 @@ static void qtest_event(void *opaque, QEMUChrEvent event)
>>          }
>>          break;
>>      case CHR_EVENT_CLOSED:
>> +        if (!qtest_opened) {
>> +            /* Ignore CLOSED events if we have already closed the log */
>> +            break;
>> +        }
>>          qtest_opened = false;
>>          if (qtest_log_fp) {
>>              fprintf(qtest_log_fp, "[I +" FMT_timeval "] CLOSED\n", g_timer_elapsed(timer, NULL));
>> --
>> 2.43.0

I'm aware some qtest stuff is lingering on the list, I came back from
vacations yesterday and will give attention to it in the next few days.

Reviewed-by: Fabiano Rosas <farosas@suse.de>