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

["Jastrzebski, MichalX K" <michalx.k.jastrzebski@intel.com>]

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mrzyglod, DanielX
> T
> Sent: Wednesday, June 08, 2016 1:41 PM
> To: Stephen Hemminger <stephen@networkplumber.org>; Kobylinski,
> MichalX <michalx.kobylinski@intel.com>
> Cc: thomas.monjalon@6wind.com; dev@dpdk.org;
> david.marchand@6wind.com
> Subject: Re: [dpdk-dev] [PATCH] mem: fix overflowed return value
> 
> 
> 
> >-----Original Message-----
> >From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen
> Hemminger
> >Sent: Friday, April 22, 2016 6:25 PM
> >To: Kobylinski, MichalX <michalx.kobylinski@intel.com>
> >Cc: thomas.monjalon@6wind.com; dev@dpdk.org
> >Subject: Re: [dpdk-dev] [PATCH] mem: fix overflowed return value
> >
> >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
> 
> From my point of view it's False Possitive there is no chance that page_size
> will be bigger than  long.
> Coverity Assume that page_size may be 18446744071562067968 but it can't.
> 
> Only for glibc<2.1 we probably should change page_size = getpagesize();   to
> page_size = sysconf(_SC_PAGESIZE);
> May I change this Coverity to False Positive or I missed something ? What's
> your opinion ?

Hi David,
What is Your opinion about classifying this defect as false/positive? 
We would like to move forward with this work.

Michal