>-----Original Message----- >From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Stephen Hemminger >Sent: Friday, April 22, 2016 6:25 PM >To: Kobylinski, MichalX <michalx.kobylinski at intel.com> >Cc: thomas.monjalon at 6wind.com; dev at 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 at 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 at 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 ?
