----- Original Message ----- > From: "Wanlong Gao" <[email protected]> > To: "Jan Stancek" <[email protected]> > Cc: [email protected], "Om Prakash PAL" > <[email protected]> > Sent: Wednesday, 24 October, 2012 9:03:16 AM > Subject: Re: [LTP] Regarding shmat01 syscall test > > On 10/24/2012 02:43 PM, Jan Stancek wrote: > > > > > > ----- Original Message ----- > >> From: "Wanlong Gao" <[email protected]> > >> To: "Om Prakash PAL" <[email protected]> > >> Cc: [email protected] > >> 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:[email protected]] > >>> Sent: Tuesday, October 23, 2012 3:07 PM > >>> To: Om Prakash PAL > >>> Cc: [email protected] > >>> 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?
No, I haven't send any patch. About solution: I'm thinking, that instead of probing with shmat, we can mmap large chunk of memory, and then set base_addr somewhere in the middle and unmap the chunk. That is, using address that get_unmapped_area() is unlikely to pick. Regards, Jan > > > Thanks, > Wanlong Gao > > > > > Regards, > > Jan > > > > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Ltp-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ltp-list
