Arnd Bergmann wrote: > On Monday 06 July 2009, Michal Simek wrote: > >>> *p1 = 0xaa; *p2 = 0x55; >>> >>> >> I closed fd too. >> close(fd); >> >>> return *p1; /* returns 0xaa if broken, 0x55 if correct */ >>> } >>> > > If you close the fd between the assignment and reading > from the pointer again, the test case becomes invalid because of > timing. Closing the fd before the '*p1 = 0xaa' should be fine, > but unnecessary. > > I also realized that you might need to mark the pointers > as 'volatile' so that the compiler has to do the operations > in order. > > The result are the same. I tried to run mmap test which are in LTP and only first one failed.
Do you have any ideas what buffer could caused that problems? >>> >>> >> # ls -la existing-4k-file >> -rw-rw-r-- 1 monstr monstr 4096 Jul 6 2009 existing-4k-file >> >> # ./test-arnd >> # echo $? >> 85 >> > > Ok, so inside a single task, this does not happen. > I print output in that task and there is 0x55 too. > >> # dd if=existing-4k-file of=/dev/console count=1 2>/dev/null >> U# >> >> in file is first char U (0x55) which is IMO correct. >> > > Right, though that was not part of the test, I'd expect this in > the file even if the return value was broken. > Not in case that mmap is completely broken. This test confirm that mmap map that fd and is possible to write there. Thanks, Michal > Arnd <>< > -- Michal Simek, Ing. (M.Eng) PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663,+42-0-721842854 f: +61-7-30090663 ------------------------------------------------------------------------------ _______________________________________________ Ltp-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ltp-list
