> It was, at least in my case. Did some printk debugging and it showed > that the hangup callback was entered what freed the serial device. Ok > > > > This is only a lockdep warning, and I don't understand its > > > significance. Even worse, when I plugged in a USB flash drive > > > afterward this appeared: > > > > Looks like something freed the resources but didn't hang up when the > > disconnect occurred > > Probably the real fix would be to let the tty layer know the device died > from the hangup handler. The hangup event means the physical hardware must no longer be touched so that's already the case and we use it for a lot of things (from ISAPnP to PCMCIA to USB). The USB code does slightly misimplement it - it calls tty_hangup() in usb_serial_disconnect when it should call tty_vhangup() as it needs the event to be synchronous. That is the hangup of the tty should be done before the USB layer can sneak off and free stuff. I don't at this point see that as explaining the bug however -- 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
