Report an error instead of segfaulting when attaching a USB device to a machine with no USB busses:
$ qemu-system-arm -machine vexpress-a9 \ -sd Fedora-17-armhfp-vexpress-mmcblk0.img \ -kernel vmlinuz-3.4.2-3.fc17.armv7hl \ -initrd initramfs-3.4.2-3.fc17.armv7hl.img \ -usbdevice disk:format=raw:test.img Note that the vexpress-a9 machine does not have a USB host controller. Reported-by: David Abdurachmanov <david.abdurachma...@cern.ch> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> --- hw/usb/bus.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/usb/bus.c b/hw/usb/bus.c index 99aac7a..55d0edd 100644 --- a/hw/usb/bus.c +++ b/hw/usb/bus.c @@ -590,6 +590,13 @@ USBDevice *usbdevice_create(const char *cmdline) return NULL; } + if (!bus) { + error_report("Error: no usb bus to attach usbdevice %s, " + "please try -machine usb=on and check that " + "the machine model supports USB", driver); + return NULL; + } + if (!f->usbdevice_init) { if (*params) { error_report("usbdevice %s accepts no params", driver); -- 1.8.0