> From: Souradeep Chakrabarti <schakrabarti@xxxxxxxxxxxxxxxxxxx> > Sent: Tuesday, January 30, 2024 2:16 AM > [...] > In commit ac5047671758 ("hv_netvsc: Disable NAPI before closing the > VMBus channel"), napi_disable was getting called for all channels, > including all subchannels without confirming if they are enabled or not. s/enabled/created/ > Which caused hv_netvsc getting hung at napi_disable, when > netvsc_probe() > and netvsc_remove() are happening simultaneously and netvsc_remove() Technically, they are not happening simultaneously: netvsc_probe() itself has finished, but the work item scheduled by it has not started yet. > calls cancel_work_sync(&nvdev->subchan_work) before netvsc_sc_open() > calls napi_enable for the sub channels. Which causes NAPIF_STATE_SCHED Technically, nvdev->subchan_work has not started to run yet, i.e. netvsc_subchan_work() -> rndis_set_subchannel() has not created the sub-channels yet, so netvsc_sc_open() can't run. It would be great if you could briefly explain how the NAPIF_STATE_SCHED bit is set and cleared, e.g. it's pre-set in rndis_filter_device_add() -> netif_napi_add() so if the sub-channels are not created, netvsc_sc_open() -> napi_enable() won't clear the flag and the flag remains set for ever for the sub-channels. > bit not getting cleared for the subchannels. > > Now during netvsc_device_remove(), when napi_disable is called for those > subchannels, napi_disable gets stuck on infinite msleep. The patch body looks good to me. Please post v2 with an updated changelog. Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>