[PATCH v5 1/5] bug/kunit: Core support for suppressing warning backtraces

[Peter Zijlstra]

On Mon, May 26, 2025 at 01:27:51PM +0000, Alessandro Carminati wrote:

>  #define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
>  #define __WARN_printf(taint, arg...) do {				\
> -		instrumentation_begin();				\
> -		__warn_printk(arg);					\
> -		__WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
> -		instrumentation_end();					\
> +		if (!KUNIT_IS_SUPPRESSED_WARNING(__func__)) {		\
> +			instrumentation_begin();			\
> +			__warn_printk(arg);				\
> +			__WARN_FLAGS(BUGFLAG_NO_CUT_HERE |		\
> +				BUGFLAG_TAINT(taint));			\
> +			instrumentation_end();				\
> +		}							\
>  	} while (0)
>  #define WARN_ON_ONCE(condition) ({				\
>  	int __ret_warn_on = !!(condition);			\
> -	if (unlikely(__ret_warn_on))				\
> +	if (unlikely(__ret_warn_on) && !KUNIT_IS_SUPPRESSED_WARNING(__func__))	\
>  		__WARN_FLAGS(BUGFLAG_ONCE |			\
>  			     BUGFLAG_TAINT(TAINT_WARN));	\
>  	unlikely(__ret_warn_on);				\
> @@ -121,7 +130,7 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
>  #ifndef WARN_ON
>  #define WARN_ON(condition) ({						\
>  	int __ret_warn_on = !!(condition);				\
> -	if (unlikely(__ret_warn_on))					\
> +	if (unlikely(__ret_warn_on) && !KUNIT_IS_SUPPRESSED_WARNING(__func__))	\
>  		__WARN();						\
>  	unlikely(__ret_warn_on);					\
>  })
> @@ -138,7 +147,7 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
>  
>  #define WARN_TAINT(condition, taint, format...) ({			\
>  	int __ret_warn_on = !!(condition);				\
> -	if (unlikely(__ret_warn_on))					\
> +	if (unlikely(__ret_warn_on) && !KUNIT_IS_SUPPRESSED_WARNING(__func__))	\
>  		__WARN_printf(taint, format);				\
>  	unlikely(__ret_warn_on);					\
>  })
> @@ -157,8 +166,10 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
>  #else /* !CONFIG_BUG */
>  #ifndef HAVE_ARCH_BUG
>  #define BUG() do {		\
> -	do {} while (1);	\
> -	unreachable();		\
> +	if (!KUNIT_IS_SUPPRESSED_WARNING(__func__)) {			\
> +		do {} while (1);					\
> +		unreachable();						\
> +	}								\
>  } while (0)
>  #endif

NAK

This is again doing it wrong -- this will bloat every frigging bug/warn
site for no reason. 

Like I said before; you need to do this on the report_bug() size of
things.