Stephen,

I got the below oops and the first bad commit is

commit 457583af4aef89d5252769ea290a2acc89e2361f
Author: Stephen Rothwell <sfr@canb.auug.org.au>
Date:   Mon Feb 4 18:12:17 2013 +1100

    memory-hotplug: common APIs to support page tables hot-remove fix fix
    
    Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

I see no direct relationship between the change and oops message,
however I tried two bisects and they both converge to the above
commit.

[   34.746615] cryptomgr_test (42) used greatest stack depth: 6776 bytes left
[   34.802868] ------------[ cut here ]------------
[   34.803941] WARNING: at /c/kernel-tests/src/stable/lib/debugobjects.c:261 debug_print_object+0x7c/0x8d()
[   34.804548] Hardware name: Bochs
[   34.804548] ODEBUG: init active (active state 0) object type: percpu_counter hint:           (null)
[   34.804548] Pid: 1, comm: swapper/0 Not tainted 3.8.0-rc6-09234-g457583a #40
[   34.804548] Call Trace:
[   34.804548]  [<ffffffff8135da31>] ? debug_print_object+0x7c/0x8d
[   34.804548]  [<ffffffff81059ee7>] warn_slowpath_common+0x79/0x94
[   34.804548]  [<ffffffff81059f5d>] warn_slowpath_fmt+0x41/0x43
[   34.804548]  [<ffffffff8135da31>] debug_print_object+0x7c/0x8d
[   34.804548]  [<ffffffff8135dbe6>] ? __debug_object_init+0x3d/0x333
[   34.804548]  [<ffffffff8135de91>] __debug_object_init+0x2e8/0x333
[   34.804548]  [<ffffffff8135def0>] debug_object_init+0x14/0x16
[   34.804548]  [<ffffffff813665b4>] __percpu_counter_init+0x6a/0xc8
[   34.804548]  [<ffffffff810ceca3>] bdi_init+0x139/0x1d1
[   34.804548]  [<ffffffff8284b327>] swap_setup+0x38/0x84
[   34.804548]  [<ffffffff8284b385>] kswapd_init+0x12/0x77
[   34.804548]  [<ffffffff8284b373>] ? swap_setup+0x84/0x84
[   34.804548]  [<ffffffff82830e32>] do_one_initcall+0x7a/0x134
[   34.804548]  [<ffffffff82830ff7>] kernel_init_freeable+0x10b/0x19a
[   34.804548]  [<ffffffff82830689>] ? loglevel+0x31/0x31
[   34.804548]  [<ffffffff81d4234f>] ? rest_init+0xc3/0xc3
[   34.804548]  [<ffffffff81d42358>] kernel_init+0x9/0xd6
[   34.804548]  [<ffffffff81d6b37c>] ret_from_fork+0x7c/0xb0
[   34.804548]  [<ffffffff81d4234f>] ? rest_init+0xc3/0xc3
[   34.804548] ---[ end trace 4b830e8d096c7c64 ]---

git bisect start 457583af4aef89d5252769ea290a2acc89e2361f v3.7 --
git bisect good b4c582a92f41417154131083127e24b66cc4b31b  #    10  2013-02-08 11:31:44  serial: xilinx_uartps: get clock rate info from dts
git bisect good 24d32e96c394bb84ca30dc41f8995efb3efa0b2e  #    10  2013-02-08 11:41:36  Merge remote-tracking branch 'sound/for-next'
git bisect good 86159e4b9bc1270344a890d368ab08d91a373c0b  #    10  2013-02-08 11:50:32  Merge remote-tracking branch 'workqueues/for-next'
git bisect good 32165b5ad1f88636cf5b7768cbf33cea74989211  #    10  2013-02-08 11:59:39  Merge remote-tracking branch 'char-misc/char-misc-next'
git bisect good edbbe0c1f464400706358f91d0b9a308e56cf50f  #    10  2013-02-08 12:11:42  Merge remote-tracking branch 'samsung/for-next'
git bisect good c5ec1c273c49037e833f096c4f591abae8c41c01  #    10  2013-02-08 12:20:33  compat: return -EFAULT on error in waitid()
git bisect good e4fde7764bf589399a6060596cca195f3fce15ff  #    10  2013-02-08 12:27:14  get_maintainer.pl: find maintainers for removed files
git bisect good 6710fc9562f4016222677534277ea442ff028ea1  #    10  2013-02-08 12:33:37  hfsplus: add support of manipulation by attributes file
git bisect good 960468a8cda8ab71a846b668a03e85c08f3543c0  #    10  2013-02-08 12:37:42  wait: add wait_event_hrtimeout()
git bisect good 29ce58899628f7c1de594b4c51a57129b9d28dae  #    10  2013-02-08 12:41:41  aio-dont-include-aioh-in-schedh-fix-fix
git bisect good bf5b05d942033ed019a3daef9651ccb172c50a2a  #    10  2013-02-08 12:46:53  block-aio-batch-completion-for-bios-kiocbs-fix-fix-fix-fix-fix-fix
git bisect good 04e0961ab478b63f81d6976e50b5642fcfaf80c9  #    10  2013-02-08 12:54:30  aio: fix aio_read_events_ring() types
git bisect good ec32b1df9515509c7ced856ea2f687d0ae51fe27  #    10  2013-02-08 12:59:23  kfifo: fix kfifo_alloc() and kfifo_init()
git bisect good 0e4ef6ad789dc7fedeaf347d013521bffe685480  #    10  2013-02-08 13:03:06  swap-add-per-partition-lock-for-swapfile-fix-fix-fix-fix
git bisect good 0e4ef6ad789dc7fedeaf347d013521bffe685480  #    30  2013-02-08 13:15:16  swap-add-per-partition-lock-for-swapfile-fix-fix-fix-fix
git bisect  bad 99ae5387e08311e47931836be5136d9df9e94cb2  #     0  2013-02-08 13:18:32  Add linux-next specific files for 20130205

Thanks,
Fengguang