Re: [LTP] Regarding shmat01 syscall test

Jan Stancek
2012-10-24T06:43:22Z

----- Original Message -----
> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
> To: "Om Prakash PAL" <omprakash.pal@stericsson.com>
> Cc: ltp-list@lists.sourceforge.net
> Sent: Wednesday, 24 October, 2012 2:45:47 AM
> Subject: Re: [LTP] Regarding shmat01 syscall test
>
> On 10/23/2012 06:05 PM, Om Prakash PAL wrote:
> >
> >
> > -----Original Message-----
> > From: Wanlong Gao [mailto:gaowanlong@cn.fujitsu.com]
> > Sent: Tuesday, October 23, 2012 3:07 PM
> > To: Om Prakash PAL
> > Cc: ltp-list@lists.sourceforge.net
> > Subject: Re: [LTP] Regarding shmat01 syscall test
> >
> > On 10/23/2012 05:24 PM, Om Prakash PAL wrote:
> >> Hi,
> >>
> >> I am working on syscall test: shmat01.c
> >>
> >> I have some confusion:
> >>
> >>
> >>
> >> In setup() : it is allocating shared memory by shmget() and then
> >> attaching by shmat() and after that detaching the attached
> >> address (i.e. shmdt())
> >>
> >>
> >>
> >> if (shmdt((const void *)base_addr) == -1) {
> >>
> >> tst_brkm(TBROK, cleanup, "Couldn't detach shared
> >> memory");
> >>
> >> }
> >>
> >>
> >>
> >> And again in main function it is using same "base_addr" as
> >> attaching address,
> >>
> >>
> >>
> >> addr = shmat(*(TC[i].shmid), base_addr+TC[i].offset,
> >>
> >> TC[i].flags);
> >>
> >> how can we ensure(100%) that base_addr (virtual) will be free till
> >> this point for attaching?.
> >
> > Maybe we can't, but I didn't see any fail on this. Did you see any
> > testing failure here?
> >
> > Yes, I got some failure and the reason of failure is : the address
> > at which we want to attach is busy.
>
> OK, please feel free to send a patch, or can you tell us how to
> reproduce it?

I recall I could reproduce it, if I added single printf:
http://article.gmane.org/gmane.linux.ltp/16480

Regards,
Jan