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

[Laurent Vivier <lvivier@redhat.com>]

On 11/7/25 18:43, Peter Maydell 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));

Reviewed-by: Laurent Vivier <lvivier@redhat.com>