FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
commit 8fcf2cc768acd845c1fed837bf9cfe2d7106336d ("watchdog: add watchdog_cpumask sysctl to assist nohz")


+------------------------------------------+------------+------------+
|                                          | ac2a46075f | 8fcf2cc768 |
+------------------------------------------+------------+------------+
| boot_successes                           | 32         | 0          |
| early-boot-hang                          | 1          |            |
| boot_failures                            | 0          | 30         |
| BUG:unable_to_handle_kernel              | 0          | 30         |
| Oops                                     | 0          | 30         |
| RIP:find_first_bit                       | 0          | 30         |
| Kernel_panic-not_syncing:Fatal_exception | 0          | 30         |
| backtrace:lockup_detector_init           | 0          | 30         |
| backtrace:kernel_init_freeable           | 0          | 30         |
+------------------------------------------+------------+------------+


[    0.066023] TSC deadline timer enabled
[    0.066995] smpboot: CPU0: Intel Core Processor (Haswell) (fam: 06, model: 3c, stepping: 01)
[    0.068023] Performance Events: unsupported p6 CPU model 60 no PMU driver, software events only.
[    0.069756] BUG: unable to handle kernel NULL pointer dereference at           (null)
[    0.070000] IP: [<ffffffff81431e39>] find_first_bit+0x9/0x60
[    0.070000] PGD 0 
[    0.070000] Oops: 0000 [#1] SMP 
[    0.070000] Modules linked in:
[    0.070000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.1.0-rc1-next-20150501-01653-gf4f4e07 #7
[    0.070000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[    0.070000] task: ffff880036f08000 ti: ffff880036f04000 task.ti: ffff880036f04000
[    0.070000] RIP: 0010:[<ffffffff81431e39>]  [<ffffffff81431e39>] find_first_bit+0x9/0x60
[    0.070000] RSP: 0000:ffff880036f07e68  EFLAGS: 00010202
[    0.070000] RAX: 00000000ee6b2800 RBX: 0000000000000002 RCX: 000000000000001b
[    0.070000] RDX: ffffffff82200280 RSI: 0000000000000002 RDI: 0000000000000000
[    0.070000] RBP: ffff880036f07e68 R08: 0000000000000010 R09: 000000000000001f
[    0.070000] R10: 00000000a13c5bac R11: 000000000000001a R12: 0000000000000000
[    0.070000] R13: 0000000000002780 R14: 0000000000000000 R15: 0000000000000000
[    0.070000] FS:  0000000000000000(0000) GS:ffff880037200000(0000) knlGS:0000000000000000
[    0.070000] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.070000] CR2: 0000000000000000 CR3: 0000000001cb7000 CR4: 00000000000406f0
[    0.070000] Stack:
[    0.070000]  ffff880036f07e88 ffffffff81eb8e33 ffffffff82200280 ffffffff820214f8
[    0.070000]  ffff880036f07f38 ffffffff81e920b8 0000000000000001 0000000000000000
[    0.070000]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[    0.070000] Call Trace:
[    0.070000]  [<ffffffff81eb8e33>] lockup_detector_init+0x33/0x79
[    0.070000]  [<ffffffff81e920b8>] kernel_init_freeable+0x128/0x248
[    0.070000]  [<ffffffff818bb990>] ? rest_init+0x90/0x90
[    0.070000]  [<ffffffff818bb99e>] kernel_init+0xe/0xf0
[    0.070000]  [<ffffffff818d0fa2>] ret_from_fork+0x42/0x70
[    0.070000]  [<ffffffff818bb990>] ? rest_init+0x90/0x90
[    0.070000] Code: 66 90 48 83 c4 28 48 89 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55 48 85 f6 48 89 e5 74 4b <48> 8b 0f 48 83 c7 08 ba 40 00 00 00 48 85 c9 74 19 eb 21 0f 1f 
[    0.070000] RIP  [<ffffffff81431e39>] find_first_bit+0x9/0x60
[    0.070000]  RSP <ffff880036f07e68>
[    0.070000] CR2: 0000000000000000
[    0.070000] ---[ end trace 94e3b40ec52f43d8 ]---
[    0.070000] Kernel panic - not syncing: Fatal exception



Thanks,
Ying Huang