On Thu, Jul 16, 2026, 11:11 PM Daniel P. Berrangé <[email protected]> wrote:
> On Thu, Jul 16, 2026 at 10:40:31PM +0800, Zhang Chen wrote: > > Based on monitor QOM path tracking iothread users with holder. > > Introduce the AioContext in the Monitor struct to avoid repeated calls to > > iothread_get_aio_context() and ensure symmetrical ref/unref during > > monitor lifecycle. > > > > Signed-off-by: Zhang Chen <[email protected]> > > --- > > monitor/monitor-internal.h | 3 +++ > > monitor/monitor.c | 22 ++++++++++++++++++++-- > > monitor/qmp.c | 5 +++-- > > 3 files changed, 26 insertions(+), 4 deletions(-) > > > > diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h > > index 23829f32f9..caecceec93 100644 > > --- a/monitor/monitor-internal.h > > +++ b/monitor/monitor-internal.h > > @@ -153,6 +153,9 @@ struct Monitor { > > guint out_watch; > > int mux_out; > > int reset_seen; > > + > > + /* iothread context */ > > + AioContext *ctx; > > }; > > > > struct MonitorHMPClass { > > diff --git a/monitor/monitor.c b/monitor/monitor.c > > index ed195fd97b..688bb85c81 100644 > > --- a/monitor/monitor.c > > +++ b/monitor/monitor.c > > @@ -573,7 +573,7 @@ void monitor_suspend(Monitor *mon) > > * Kick I/O thread to make sure this takes effect. It'll be > > * evaluated again in prepare() of the watch object. > > */ > > - aio_notify(iothread_get_aio_context(mon_iothread)); > > + aio_notify(mon->ctx); > > } > > > > trace_monitor_suspend(mon, 1); > > @@ -668,6 +668,17 @@ void monitor_cleanup(void) > > qemu_mutex_unlock(&monitor_lock); > > monitor_flush(mon); > > qemu_mutex_lock(&monitor_lock); > > + > > + if (mon_iothread) { > > + g_autofree char *path = > object_get_canonical_path(OBJECT(mon)); > > + const IOThreadHolder io_holder = { > > + .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT, > > + .u.qom_object.qom_path = path, > > + }; > > + > > + iothread_put_aio_context(mon_iothread, &io_holder); > > + mon->ctx = NULL; > > + } > > object_unparent(OBJECT(mon)); > > } > > qemu_mutex_unlock(&monitor_lock); > > @@ -732,7 +743,14 @@ static void monitor_complete(UserCreatable *uc, > Error **errp) > > mon_iothread = iothread_create("mon_iothread", > &error_abort); > > } > > > > - ctx = iothread_get_aio_context(mon_iothread); > > + g_autofree char *path = object_get_canonical_path(OBJECT(mon)); > > + const IOThreadHolder io_holder = { > > + .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT, > > + .u.qom_object.qom_path = path, > > + }; > > + > > + mon->ctx = iothread_ref_and_get_aio_context(mon_iothread, > &io_holder); > > + ctx = mon->ctx; > > } else { > > ctx = qemu_get_aio_context(); > > } > > Even though QMP only takes the first branch, I'd be more > comfortable if we set mon->ctx in both branches of this > condition, so we can always assume that mon->ctx is > non-NULL. > Good catch，I will send a RESEND version for v10 as a quick fix. Thanks Chen > > diff --git a/monitor/qmp.c b/monitor/qmp.c > > index 223e0643c2..b16bd77688 100644 > > --- a/monitor/qmp.c > > +++ b/monitor/qmp.c > > @@ -732,7 +732,8 @@ static void monitor_qmp_complete(UserCreatable *uc, > Error **errp) > > * thread. Schedule a bottom half. > > */ > > mon->setup_pending = true; > > - aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread), > > + > > + aio_bh_schedule_oneshot(MONITOR(mon)->ctx, > > monitor_qmp_setup_handlers_bh, mon); > > /* The bottom half will add @mon to @mon_list */ > > } else { > > @@ -787,7 +788,7 @@ static bool monitor_qmp_prepare_delete(UserCreatable > *uc, Error **errp) > > > > /* Synchronize with in-flight iothread callbacks. */ > > if (monitor_requires_iothread(mon)) { > > - aio_wait_bh_oneshot(iothread_get_aio_context(mon_iothread), > > + aio_wait_bh_oneshot(MONITOR(mon)->ctx, > > monitor_qmp_iothread_quiesce, NULL); > > } > > ...this unconditionally accesses mon->ctx, and so will surely hit > a NULL > > > > > -- > > 2.49.0 > > > > With regards, > Daniel > -- > |: https://berrange.com ~~ https://hachyderm.io/@berrange :| > |: https://libvirt.org ~~ https://entangle-photo.org :| > |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :| > >
