v2.6.26-rc7: BUG task_struct: Poison overwritten

[Vegard Nossum <vegard.nossum@gmail.com>]

Hi,

I don't really know what to do about this. The stacktrace is utterly
uninteresting, too. Maybe you can extract some information from it?
I was running lmbench and hotplug/-unplugging CPUs, some network-
exercising code, and a grep on /sys.

I have the config and vmlinux with debugging symbols if this is needed.

Thanks.


Vegard


 =============================================================================
 BUG task_struct: Poison overwritten
 -----------------------------------------------------------------------------
 
 INFO: 0xeb2f3018-0xeb2f302b. First byte 0x35 instead of 0x6b
 INFO: Allocated in copy_process+0x70/0x1090 age=326 cpu=1 pid=2109
 INFO: Freed in free_task+0x2c/0x30 age=283 cpu=0 pid=19516
 INFO: Slab 0xc1974480 objects=8 used=7 fp=0xeb2f2fd0 flags=0x400020c3
 INFO: Object 0xeb2f2fd0 @offset=12240 fp=0x00000000
 
 Bytes b4 0xeb2f2fc0:  5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
   Object 0xeb2f2fd0:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
   Object 0xeb2f2fe0:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
   Object 0xeb2f2ff0:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
   Object 0xeb2f3000:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
   Object 0xeb2f3010:  6b 6b 6b 6b 6b 6b 6b 6b 35 cc 4a 6a 1f 08 00 00 kkkkkkkk5<CC>Jj....
   Object 0xeb2f3020:  35 cc 4a 6a 6c 6b 6b 6b 6a 6b 6b eb 6b 6b 6b 6b 5<CC>Jjlkkkjkk<EB>kkkk
   Object 0xeb2f3030:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
   Object 0xeb2f3040:  6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
  Redzone 0xeb2f3f88:  bb bb bb bb                                     <BB><BB><BB><BB>            
  Padding 0xeb2f3fb0:  5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
 Pid: 1326, comm: udevd Not tainted 2.6.26-rc7 #25
  [<c018f3fa>] print_trailer+0xaa/0xe0
  [<c018f4cb>] check_bytes_and_report+0x9b/0xc0
  [<c018f8b3>] check_object+0x193/0x1f0
  [<c019047b>] __slab_alloc+0x44b/0x5d0
  [<c01909e3>] kmem_cache_alloc+0xb3/0xe0
  [<c01345c0>] ? copy_process+0x70/0x1090
  [<c01345c0>] ? copy_process+0x70/0x1090
  [<c01345c0>] copy_process+0x70/0x1090
  [<c017ff49>] ? remove_vma+0x49/0x60
  [<c01356d7>] do_fork+0x57/0x280
  [<c0180a8a>] ? do_munmap+0x18a/0x1f0
  [<c0180b36>] ? sys_munmap+0x46/0x60
  [<c010652f>] sys_clone+0x2f/0x40
  [<c010831b>] sysenter_past_esp+0x78/0xd1
  =======================
 FIX task_struct: Restoring 0xeb2f3018-0xeb2f302b=0x6b
 
 FIX task_struct: Marking all objects used