Re: [PATCH] [v2] bug: avoid format attribute warning for clang as well

[Brendan Jackman]

On Mon Mar 23, 2026 at 8:55 PM UTC, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> Like gcc, clang-22 now also warns about a function that it
> incorrectly identifies as a printf-style format:
>
> lib/bug.c:190:22: error: diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of '__warn_printf' [-Werror,-Wmissing-format-attribute]
>   179 | static void __warn_printf(const char *fmt, struct pt_regs *regs)
>       | __attribute__((format(printf, 1, 0)))
>   180 | {
>   181 |         if (!fmt)
>   182 |                 return;
>   183 |
>   184 | #ifdef HAVE_ARCH_BUG_FORMAT_ARGS
>   185 |         if (regs) {
>   186 |                 struct arch_va_list _args;
>   187 |                 va_list *args = __warn_args(&_args, regs);
>   188 |
>   189 |                 if (args) {
>   190 |                         vprintk(fmt, *args);
>       |                                           ^
>
> Revert the change that added a gcc-specific workaround, and instead add
> the generic annotation that avoid the warning.
>
> Fixes: d36067d6ea00 ("bug: Hush suggest-attribute=format for __warn_printf()")
> Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Suggested-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
> Link: https://lore.kernel.org/all/20251208141618.2805983-1-andriy.shevchenko@xxxxxxxxxxxxxxx/T/#u
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Thank you,

Reviewed-by: Brendan Jackman <jackmanb@xxxxxxxxxx>