Re: [dpdk-dev] [PATCH] mem: fix overflowed return value

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 22 Apr 2016 12:44:18 +0200
Michal Kobylinski <michalx.kobylinski@intel.com> wrote:

> Fix issue reported by Coverity.
> 
> Coverity ID 13255: Overflowed return value: The return value will be too
> small or even negative, likely resulting in unexpected behavior in a
> caller that uses the return value. In rte_mem_virt2phy: An integer
> overflow occurs, with the overflowed value used as the return value of
> the function
> 
> Fixes: 3097de6e6bfb ("mem: get physical address of any pointer")
> 
> Signed-off-by: Michal Kobylinski <michalx.kobylinski@intel.com>
> ---
>  lib/librte_eal/linuxapp/eal/eal_memory.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 5b9132c..6ceca5b 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -195,7 +195,7 @@ rte_mem_virt2phy(const void *virtaddr)
>  	 * the pfn (page frame number) are bits 0-54 (see
>  	 * pagemap.txt in linux Documentation)
>  	 */
> -	physaddr = ((page & 0x7fffffffffffffULL) * page_size)
> +	physaddr = (uint64_t)((page & 0x7fffffffffffffULL) * page_size)
>  		+ ((unsigned long)virtaddr % page_size);
>  	close(fd);
>  	return physaddr;

I am not trusting any of these Coverity patches you are sending.
It seems you think wraparound can be just fixed by casting, it can't