Subject: Re: [PATCH 02/14] kunit: bug: Count suppressed warning backtraces

From: Kees Cook <[email-masked]>
Date: Tue, 12 Mar 2024 15:02:05 -0700

On Tue, Mar 12, 2024 at 10:02:57AM -0700, Guenter Roeck wrote:
> Count suppressed warning backtraces to enable code which suppresses
> warning backtraces to check if the expected backtrace(s) have been
> observed.
> 
> Using atomics for the backtrace count resulted in build errors on some
> architectures due to include file recursion, so use a plain integer
> for now.
> 
> Signed-off-by: Guenter Roeck <[email-masked]>
> ---
>  include/kunit/bug.h | 7 ++++++-
>  lib/kunit/bug.c     | 4 +++-
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/include/kunit/bug.h b/include/kunit/bug.h
> index 1e34da961599..2097a854ac8c 100644
> --- a/include/kunit/bug.h
> +++ b/include/kunit/bug.h
> @@ -20,6 +20,7 @@
>  struct __suppressed_warning {
>  	struct list_head node;
>  	const char *function;
> +	int counter;

Thanks for adding a counter!

>  };
>  
>  void __start_suppress_warning(struct __suppressed_warning *warning);
> @@ -28,7 +29,7 @@ bool __is_suppressed_warning(const char *function);
>  
>  #define DEFINE_SUPPRESSED_WARNING(func)	\
>  	struct __suppressed_warning __kunit_suppress_##func = \
> -		{ .function = __stringify(func) }
> +		{ .function = __stringify(func), .counter = 0 }
>  
>  #define START_SUPPRESSED_WARNING(func) \
>  	__start_suppress_warning(&__kunit_suppress_##func)
> @@ -39,12 +40,16 @@ bool __is_suppressed_warning(const char *function);
>  #define IS_SUPPRESSED_WARNING(func) \
>  	__is_suppressed_warning(func)
>  
> +#define SUPPRESSED_WARNING_COUNT(func) \
> +	(__kunit_suppress_##func.counter)
> +
>  #else /* CONFIG_KUNIT */
>  
>  #define DEFINE_SUPPRESSED_WARNING(func)
>  #define START_SUPPRESSED_WARNING(func)
>  #define END_SUPPRESSED_WARNING(func)
>  #define IS_SUPPRESSED_WARNING(func) (false)
> +#define SUPPRESSED_WARNING_COUNT(func) (0)
>  
>  #endif /* CONFIG_KUNIT */
>  #endif /* __ASSEMBLY__ */
> diff --git a/lib/kunit/bug.c b/lib/kunit/bug.c
> index f93544d7a9d1..13b3d896c114 100644
> --- a/lib/kunit/bug.c
> +++ b/lib/kunit/bug.c
> @@ -32,8 +32,10 @@ bool __is_suppressed_warning(const char *function)
>  		return false;
>  
>  	list_for_each_entry(warning, &suppressed_warnings, node) {
> -		if (!strcmp(function, warning->function))
> +		if (!strcmp(function, warning->function)) {
> +			warning->counter++;
>  			return true;
> +		}
>  	}
>  	return false;
>  }
> -- 
> 2.39.2
> 

Reviewed-by: Kees Cook <[email-masked]>

-- 
Kees Cook