Re: [Qemu-devel] [PATCH v2 2/5] hw/usb/hcd-xhci: Fix GCC 9 build warning

[Daniel P . Berrangé]

On Tue, Apr 30, 2019 at 11:28:31PM +0000, Alistair Francis wrote:
> Fix this build warning with GCC 9 on Fedora 30:
> hw/usb/hcd-xhci.c:3339:66: error: ‘%d’ directive output may be truncated 
> writing between 1 and 10 bytes into a region of size 5 
> [-Werror=format-truncation=]
>  3339 |             snprintf(port->name, sizeof(port->name), "usb2 port #%d", 
> i+1);
>       |                                                                  ^~
> hw/usb/hcd-xhci.c:3339:54: note: directive argument in the range [1, 
> 2147483647]
>  3339 |             snprintf(port->name, sizeof(port->name), "usb2 port #%d", 
> i+1);
>       |                                                      ^~~~~~~~~~~~~~~
> In file included from /usr/include/stdio.h:867,
>                  from /home/alistair/qemu/include/qemu/osdep.h:99,
>                  from hw/usb/hcd-xhci.c:21:
> /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output 
> between 13 and 22 bytes into a destination of size 16
>    67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
>       |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    68 |        __bos (__s), __fmt, __va_arg_pack ());
>       |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Alistair Francis <address@hidden>
> ---
>  hw/usb/hcd-xhci.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index ec28bee319..2b061772b2 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -3322,6 +3322,7 @@ static void usb_xhci_init(XHCIState *xhci)
>      usb_bus_new(&xhci->bus, sizeof(xhci->bus), &xhci_bus_ops, dev);
>  
>      for (i = 0; i < usbports; i++) {
> +        g_assert(i < MAX(MAXPORTS_2, MAXPORTS_3));
>          speedmask = 0;
>          if (i < xhci->numports_2) {
>              if (xhci_get_flag(xhci, XHCI_FLAG_SS_FIRST)) {

I proposed a slightly different fix here:

  https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02125.html

but both have the same effect


  Reviewed-by: Daniel P. Berrangé <address@hidden>


Regards,
Daniel
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