On Mon, 8 Aug 2011 15:38:20 -0700 Vincent Palatin <vpalatin@xxxxxxxxxxxx> wrote: > Sometimes, acm_tty_hangup and acm_tty_close are called concurrently. > This results in acm pointer being null in acm_tty_hangup and panics when > it is dereferenced. This is definitely not the way to attack the problem. The tty port hangup and close logic will do all the needed locking and do it right. The big problem here is touching tty->driver_data. If you have a block of memory that is tied to the tty object lifetime it needs to get destroyed when the tty object is destroyed not as close/hangup or you still leave races. Take a look at tty_port_close tty_port_hangup and in particular for port internal sychronization of open/close/hangup once only events at port->ops->activate port->ops->shutdown port->ops->destruct and for a tty lifetime object tty->ops->shutdown Alan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
