Re: [PATCH 1/2 v2] xhci: fix garbage USBSTS being logged in some cases

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 25.2.2022 12.26, Anssi Hannula wrote:
> xhci_decode_usbsts() is expected to return a zero-terminated string by
> its only caller, xhci_stop_endpoint_command_watchdog(), which directly
> logs the return value:
> 
>   xhci_warn(xhci, "USBSTS:%s\n", xhci_decode_usbsts(str, usbsts));
> 
> However, if no recognized bits are set in usbsts, the function will
> return without having called any sprintf() and therefore return an
> untouched non-zero-terminated caller-provided buffer, causing garbage
> to be output to log.
> 
> Fix that by always including the raw value in the output.
> 
> Note that before 4843b4b5ec64 ("xhci: fix even more unsafe memory usage
> in xhci tracing") the result effect in the failure case was different as
> a static buffer was used here, but the code still worked incorrectly.
> 
> Fixes: 9c1aa36efdae ("xhci: Show host status when watchdog triggers and host is assumed dead.")
> Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
> ---

Thanks. Adding both 1/2 v2 and 2/2

-Mathias