Re: [2.6.37-rc8] BUG kmalloc-256: Poison overwritten.

From: Pekka Enberg
Date: Thu Dec 30 2010 - 10:31:52 EST


On Thu, 2010-12-30 at 16:08 +0100, Pawel Sikora wrote:
> [ 1863.448308] =============================================================================
> [ 1863.448313] BUG kmalloc-256: Poison overwritten
> [ 1863.448315] -----------------------------------------------------------------------------
> [ 1863.448316]
> [ 1863.448319] INFO: 0xffff8807ffc7e7c4-0xffff8807ffc7e7c5. First byte 0x6c instead of 0x6b
> [ 1863.448331] INFO: Allocated in setup_conf+0x12b/0x360 [raid10] age=554800 cpu=5 pid=2766
> [ 1863.448336] INFO: Freed in stop+0x66/0x80 [raid10] age=4271 cpu=3 pid=5266
> [ 1863.448339] INFO: Slab 0xffffea001bff3b90 objects=24 used=11 fp=0xffff8807ffc7e7b0 flags=0x6000000000040c1
> [ 1863.448341] INFO: Object 0xffff8807ffc7e7b0 @offset=1968 fp=0xffff8807ffc7f338
> [ 1863.448343]
> [ 1863.448345] Bytes b4 0xffff8807ffc7e7a0: a9 c6 fe ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ïïïï....ZZZZZZZZ
> [ 1863.448353] Object 0xffff8807ffc7e7b0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448362] Object 0xffff8807ffc7e7c0: 6b 6b 6b 6b 6c 6c 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkllkkkkkkkkkk
> [ 1863.448369] Object 0xffff8807ffc7e7d0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448377] Object 0xffff8807ffc7e7e0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448384] Object 0xffff8807ffc7e7f0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448391] Object 0xffff8807ffc7e800: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448399] Object 0xffff8807ffc7e810: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448406] Object 0xffff8807ffc7e820: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448413] Object 0xffff8807ffc7e830: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448421] Object 0xffff8807ffc7e840: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448428] Object 0xffff8807ffc7e850: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448435] Object 0xffff8807ffc7e860: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448442] Object 0xffff8807ffc7e870: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448450] Object 0xffff8807ffc7e880: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448457] Object 0xffff8807ffc7e890: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> [ 1863.448464] Object 0xffff8807ffc7e8a0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkkï
> [ 1863.448472] Redzone 0xffff8807ffc7e8b0: bb bb bb bb bb bb bb bb ïïïïïïïï
> [ 1863.448478] Padding 0xffff8807ffc7e8f0: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
> [ 1863.448487] Pid: 5282, comm: udevd Not tainted 2.6.37-rc8 #1
> [ 1863.448489] Call Trace:
> [ 1863.448499] [<ffffffff8111ea1e>] print_trailer+0xfe/0x160
> [ 1863.448503] [<ffffffff8111f074>] check_bytes_and_report+0xf4/0x130
> [ 1863.448506] [<ffffffff8111f2da>] check_object+0x22a/0x270
> [ 1863.448512] [<ffffffff81137cc9>] ? do_execve+0x59/0x390
> [ 1863.448515] [<ffffffff81137cc9>] ? do_execve+0x59/0x390
> [ 1863.448519] [<ffffffff81120380>] alloc_debug_processing+0x110/0x1f0
> [ 1863.448522] [<ffffffff811211c9>] __slab_alloc+0x3a9/0x410
> [ 1863.448528] [<ffffffff8140254c>] ? do_page_fault+0x1cc/0x4b0
> [ 1863.448531] [<ffffffff81137cc9>] ? do_execve+0x59/0x390
> [ 1863.448534] [<ffffffff81121888>] kmem_cache_alloc_notrace+0xb8/0xc0
> [ 1863.448538] [<ffffffff81137cc9>] do_execve+0x59/0x390
> [ 1863.448543] [<ffffffff8121f0c1>] ? strncpy_from_user+0x31/0x50
> [ 1863.448548] [<ffffffff8100b205>] sys_execve+0x45/0x70
> [ 1863.448553] [<ffffffff8100319c>] stub_execve+0x6c/0xc0
> [ 1863.448556] FIX kmalloc-256: Restoring 0xffff8807ffc7e7c4-0xffff8807ffc7e7c5=0x6b
> [ 1863.448557]
> [ 1863.448559] FIX kmalloc-256: Marking all objects used

This looks like a use-after-free bug somewhere in drivers/md/raid10.c.

Pekka

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