RE: [PATCH] sched: fix integer handling issue

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Megha Ajmera [mailto:megha.ajmera@intel.com]
> Sent: Tuesday, 22 February 2022 14.19
> 
> Masking of core mask was incorrect. Instead of using 1U for shifting,
> it
> should be using 1LU as the result is assigned to uint64.
> 
> CID 375859: Potentially overflowing expression "1U << app_main_core"
> with
> type "unsigned int" (32 bits, unsigned) is evaluated using 32-bit
> arithmetic,
> and then used in a context that expects an expression of type
> "uint64_t"
> (64 bits, unsigned).
> 
> Coverity issue: 375859
> 
> Signed-off-by: Megha Ajmera <megha.ajmera@intel.com>
> ---
>  examples/qos_sched/args.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/qos_sched/args.c b/examples/qos_sched/args.c
> index 10ca7bea61..44f2f5640e 100644
> --- a/examples/qos_sched/args.c
> +++ b/examples/qos_sched/args.c
> @@ -433,7 +433,7 @@ app_parse_args(int argc, char **argv)
>  			return -1;
>  		}
>  	}
> -	app_used_core_mask |= 1u << app_main_core;
> +	app_used_core_mask |= 1lu << app_main_core;

Still wrong on 32 bit platforms, where long unsigned int is still 32 bits.

Use this instead:
app_used_core_mask |= RTE_BIT64(app_main_core);

Ref:
https://elixir.bootlin.com/dpdk/latest/source/lib/eal/include/rte_bitops.h#L26

> 
>  	if ((app_used_core_mask != app_eal_core_mask()) ||
>  			(app_main_core != rte_get_main_lcore())) {
> --
> 2.25.1
>