Jie Song, Marc-André, is this bug serious enough and the fix safe enough to still go into 10.2?
Jie Song <[email protected]> writes: > From: Jie Song <[email protected]> > > When starting a dummy QEMU process with virsh version, monitor_init_qmp() > enables IOThread monitoring of the QMP fd by default. However, a race > condition exists during the initialization phase: the IOThread only removes > the main thread's fd watch when it reaches > qio_net_listener_set_client_func_full(), > which may be delayed under high system load. > > This creates a window between monitor_qmp_setup_handlers_bh() and > qio_net_listener_set_client_func_full() where both the main thread and > IOThread are simultaneously monitoring the same fd and processing events. > This race can cause either the main thread or the IOThread to hang and > become unresponsive. > > Fix this by proactively cleaning up the listener's IO sources in > monitor_init_qmp() before the IOThread initializes QMP monitoring, > ensuring exclusive fd ownership and eliminating the race condition. > > Signed-off-by: Jie Song <[email protected]> > Reviewed-by: Marc-André Lureau <[email protected]>
