Greetings,

I find this BUG trace in upstream kernel with the attached kconfig:

[    5.543416] ieee80211 phy0: Failed to select rate control algorithm
[    5.543993] ieee80211 phy0: Failed to initialize rate control algorithm
[    5.556937] mac80211_hwsim: ieee80211_register_hw failed (-2)
[    5.557669] BUG: unable to handle kernel paging request at cd1aa02c
[    5.558381] IP: [<c09bd01b>] kobject_get+0x2b/0xb0
[    5.558922] *pdpt = 0000000002c20001 *pde = 000000000fbfc067 *pte = 800000000d1aa060 
[    5.559861] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[    5.560126] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-01713-g0b1e73e #964
[    5.560126] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    5.560126] task: c001e000 ti: c0020000 task.ti: c0020000
[    5.560126] EIP: 0060:[<c09bd01b>] EFLAGS: 00010246 CPU: 0
[    5.560126] EIP is at kobject_get+0x2b/0xb0
[    5.560126] EAX: 00000001 EBX: cd1aa010 ECX: 00000201 EDX: cd1a8de0
[    5.560126] ESI: c2a0a4b4 EDI: cd1ba500 EBP: c0021e6c ESP: c0021e68
[    5.560126]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[    5.560126] CR0: 8005003b CR2: cd1aa02c CR3: 02c23000 CR4: 000006b0
[    5.560126] Stack:
[    5.560126]  cd1aa008 c0021e74 c0b53a9b c0021e88 c0b5958b c2a0a4b4 fffffffe cd1ba500
[    5.560126]  c0021e94 c0b57aac c2a0a4b4 c0021eac c0b5a6bb c1f56afe c0021ea0 c0021ea0
[    5.560126]  fffffffe c0021eb4 c0b5cf29 c0021f04 c2b981e5 c27626c0 fffffffe 00000000
[    5.560126] Call Trace:
[    5.560126]  [<c0b53a9b>] get_device+0x2b/0x50
[    5.560126]  [<c0b5958b>] driver_detach+0x3b/0x180
[    5.560126]  [<c0b57aac>] bus_remove_driver+0x8c/0x150
[    5.560126]  [<c0b5a6bb>] driver_unregister+0x5b/0xa0
[    5.560126]  [<c1f56afe>] ? mac80211_hwsim_free+0x178/0x18d
[    5.560126]  [<c0b5cf29>] platform_driver_unregister+0x19/0x30
[    5.560126]  [<c2b981e5>] init_mac80211_hwsim+0x1024/0x103c
[    5.560126]  [<c2b971c1>] ? ar5523_driver_init+0x32/0x32
[    5.560126]  [<c2b2b64e>] do_one_initcall+0xfe/0x228
[    5.560126]  [<c029a101>] ? parameq+0x21/0xf0
[    5.560126]  [<c2b2a700>] ? do_early_param+0xfa/0x131
[    5.560126]  [<c029a4bb>] ? parse_args+0x2eb/0x5f0
[    5.560126]  [<c028b918>] ? __usermodehelper_set_disable_depth+0x68/0x80
[    5.560126]  [<c2b2b9d1>] kernel_init_freeable+0x259/0x3e1
[    5.560126]  [<c2b2a737>] ? do_early_param+0x131/0x131
[    5.560126]  [<c1f26219>] kernel_init+0x19/0x290
[    5.560126]  [<c1f83f77>] ret_from_kernel_thread+0x1b/0x28
[    5.560126]  [<c1f26200>] ? rest_init+0x1a0/0x1a0
[    5.560126] Code: 55 83 05 00 11 2b c3 01 83 15 04 11 2b c3 00 85 c0 89 e5 53 89 c3 74 2a 83 05 08 11 2b c3 01 b8 01 00 00 00 83 15 0c 11 2b c3 00 <f0> 0f c1 43 1c 83 05 10 11 2b c3 01 83 15 14 11 2b c3 00 40 48
[    5.560126] EIP: [<c09bd01b>] kobject_get+0x2b/0xb0 SS:ESP 0068:c0021e68
[    5.560126] CR2: 00000000cd1aa02c
[    5.560126] ---[ end trace 36f00592e60ee129 ]---
[    5.560126] Kernel panic - not syncing: Fatal exception

Thanks,
Fengguang