Re: [LTP] Regarding shmat01 syscall test

Wanlong Gao
2012-10-23T10:00:24Z

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?

Thanks,
Wanlong Gao

>
> there is possibility that this address(base_addr) will be used, so in that case this shmat() will fail.
>
> Please correct me if I am wrong.
>
> Thanks in advance.
>
>
>
> Best Regards,
>
> Om Prakash Pal
>
>
>
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