On 2017/11/6 19:32, Greg KH wrote: >> A simple process is as below: >> xhci_plat_probe() >> | >> usb_add_hcd() xhci_plat_remove() >> | | >> find some device usb_remove_hcd() >> | | >> hub_port_connect() -> usb_alloc_dev() usb_disconnect() >> | | >> before hub_enable_device() xhci_stop() >> | >> xhci_mem_cleanup() >> | >> xhci_free_virt_devices_depth_first() >> | >> real_port is 0 access xhci->rh_bw[vdev->real_port-1] >> >> The problem came from https://bugs.96boards.org/show_bug.cgi?id=535 >> Also look at crbug.com/700041 > > Then the bug needs to be fixed, throwing a huge kernel trace message > into the kernel log is not "fixing" the problem at all, right? > > thanks, > > greg k-h > > . > You are right, the way that xhci_plat_remove() to be called needs to be fixed. But there is still possibility for this crash. What do you think if just add an "xhci_warn" instead of "WARN_ON"? + if (!vdev->real_port) { + xhci_warn(xhci, "Bad vdev->real_port\n"); + goto out; + } + Best regards Yu Chen -- 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
