Re: [LTP] Regarding shmat01 syscall test

Wanlong Gao
2012-10-24T07:05:31Z

On 10/24/2012 02:43 PM, Jan Stancek wrote:
>
>
> ----- 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

Do you get a solution? Send out a patch?

Thanks,
Wanlong Gao

>
> Regards,
> Jan