Am 23.05.2017 um 23:01 schrieb Lino Sanfilippo: > On 23.05.2017 21:38, Stefan Wahren wrote: >>> Lino Sanfilippo <linosanfili...@gmx.de> hat am 23. Mai 2017 um 20:16 >>> geschrieben: >>> >>> I suggest to avoid this possible race by first unregistering the netdevice >>> and then >>> calling cancel_work_sync(). >> What makes you sure that's safe to unregister the netdev while the tx work >> queue is possibly active? > unregister_netdevice() calls netdev_close() if the interface is still up. > netdev_close() calls flush_work() > so the unregistration is delayed until the tx work function is finished. > Furthermore both close() and > tx work are synchronized by means of the qca->lock which also guarantees that > unregister_netdevice() wont > be finished until the tx work is done. >
Thanks for the explanation. I suspect there could be the same race between serdev_device_close() and the tx work queue. So i would propose a variant of your original suggestion: unregister_netdev(qca->net_dev); /* Flush any pending characters in the driver. */ serdev_device_close(serdev); cancel_work_sync(&qca->tx_work); Since we have the same pattern in the error path of the probe function, the same applies there. Stefan
