From: Peter Maydell <peter.mayd...@linaro.org> In usb_mask_to_str() we convert a mask of USB speeds into a human-readable string (like "full+high") for use in tracing and error messages. However the conversion code doesn't do anything to the string buffer if the passed in speedmask doesn't match any of the recognized speeds, which means that the tracing and error messages will end up with random garbage in them. This can happen if we're doing USB device passthrough.
Handle the "unrecognized speed" case by using the string "unknown". Fixes: https://bugs.launchpad.net/qemu/+bug/1603785 Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org> Message-id: 20190328133503.6490-1-peter.mayd...@linaro.org Signed-off-by: Gerd Hoffmann <kra...@redhat.com> --- hw/usb/bus.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/usb/bus.c b/hw/usb/bus.c index 6fffab7bfa44..9a74dc956010 100644 --- a/hw/usb/bus.c +++ b/hw/usb/bus.c @@ -500,6 +500,10 @@ static void usb_mask_to_str(char *dest, size_t size, speeds[i].name); } } + + if (pos == 0) { + snprintf(dest, size, "unknown"); + } } void usb_check_attach(USBDevice *dev, Error **errp) -- 2.18.1
