Re: [PATCH] HID: core: Fix size_t specifier in hid_report_raw_event()

[Geert Uytterhoeven]

Hi Nathan,

On Sun, 17 May 2026 at 06:51, Nathan Chancellor <nathan@xxxxxxxxxx> wrote:
> When building for 32-bit platforms, for which 'size_t' is
> 'unsigned int', there are warnings around using the incorrect format
> specifier to print bsize in hid_report_raw_event():
>
>   drivers/hid/hid-core.c:2054:29: error: format specifies type 'long' but the argument has type 'size_t' (aka 'unsigned int') [-Werror,-Wformat]
>    2053 |                 hid_warn_ratelimited(hid, "Event data for report %d is incorrect (%d vs %ld)\n",
>         |                                                                                         ~~~
>         |                                                                                         %zu
>    2054 |                                      report->id, csize, bsize);
>         |                                                         ^~~~~
>   drivers/hid/hid-core.c:2076:29: error: format specifies type 'long' but the argument has type 'size_t' (aka 'unsigned int') [-Werror,-Wformat]
>    2075 |                 hid_warn_ratelimited(hid, "Event data for report %d was too short (%d vs %ld)\n",
>         |                                                                                          ~~~
>         |                                                                                          %zu
>    2076 |                                      report->id, rsize, bsize);
>         |                                                         ^~~~~
>
> Use the proper 'size_t' format specifier, '%zu', to clear up the
> warnings.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 2c85c61d1332 ("HID: pass the buffer size to hid_report_raw_event")
> Reported-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
> Closes: https://lore.kernel.org/20260516020430.110135-1-ojeda@xxxxxxxxxx/
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>

Thanks, this fixes the warnings on 32-bit for me.

> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -2050,7 +2050,7 @@ int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *
>                 return 0;
>
>         if (unlikely(bsize < csize)) {
> -               hid_warn_ratelimited(hid, "Event data for report %d is incorrect (%d vs %ld)\n",
> +               hid_warn_ratelimited(hid, "Event data for report %d is incorrect (%d vs %zu)\n",
>                                      report->id, csize, bsize);

Both report->id and csize are unsigned, so should use %u.

>                 return -EINVAL;
>         }
> @@ -2072,7 +2072,7 @@ int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *
>                 rsize = max_buffer_size;
>
>         if (bsize < rsize) {
> -               hid_warn_ratelimited(hid, "Event data for report %d was too short (%d vs %ld)\n",
> +               hid_warn_ratelimited(hid, "Event data for report %d was too short (%d vs %zu)\n",
>                                      report->id, rsize, bsize);

Same here.

>                 return -EINVAL;
>         }

And more incorrect %d outside the context!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds