Re: [1/1] rt-tests: queuelat: Fix wraparound in __clock_gettime()

[Marcelo Tosatti <mtosatti@redhat.com>]

On Mon, Nov 11, 2024 at 09:49:11AM +0800, ende.tan@starfivetech.com wrote:
> From: Tan En De <ende.tan@starfivetech.com>
> 
> Include tv_sec in addition to tv_nsec in __clock_gettime(). If the value
> of variable 'a' wraps around, it may cause 'delta' to be negative, while
> 'delta' is defined with u64 type.
> 
> Signed-off-by: Tan En De <ende.tan@starfivetech.com>
> ---
>  src/queuelat/queuelat.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/queuelat/queuelat.c b/src/queuelat/queuelat.c
> index c549cd8..c057389 100644
> --- a/src/queuelat/queuelat.c
> +++ b/src/queuelat/queuelat.c
> @@ -292,7 +292,8 @@ static inline unsigned long long __clock_gettime(void)
>  	if (ret < 0)
>  		return 0;
>  
> -	return now.tv_nsec;
> +	// Combine seconds and nanoseconds into a single value in nanoseconds
> +	return (unsigned long long)now.tv_sec * 1000000000ULL + now.tv_nsec;
>  }
>  
>  #define gettick(val) do { (val) = __clock_gettime(); } while (0)
> -- 
> 2.34.1
> 
> 

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>