FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/wip
commit 021515523d1fd3f9e239a1bb4761882703cac9b0 ("hrtimer: Get rid of hrtimer softirq")


+-------------------------------------------------------+------------+------------+
|                                                       | 9791850cc8 | 021515523d |
+-------------------------------------------------------+------------+------------+
| boot_successes                                        | 22         | 0          |
| early-boot-hang                                       | 1          |            |
| boot_failures                                         | 0          | 19         |
| BUG:kernel_boot_crashed                               | 0          | 16         |
| kernel_BUG_at_kernel/irq_work.c                       | 0          | 3          |
| invalid_opcode                                        | 0          | 3          |
| EIP_is_at_irq_work_run_list                           | 0          | 3          |
| Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0          | 3          |
| backtrace:proc_create_data                            | 0          | 1          |
| backtrace:proc_cpuinfo_init                           | 0          | 1          |
| backtrace:kernel_init_freeable                        | 0          | 3          |
| backtrace:cpu_startup_entry                           | 0          | 1          |
| backtrace:aa_create_aafs                              | 0          | 1          |
| backtrace:kmem_cache_create                           | 0          | 1          |
| backtrace:eventpoll_init                              | 0          | 1          |
+-------------------------------------------------------+------------+------------+

[    0.129279] Switched to clocksource kvm-clock
[    0.129751] FS-Cache: Loaded
[    0.129999] ------------[ cut here ]------------
[    0.129999] kernel BUG at kernel/irq_work.c:135!
[    0.129999] invalid opcode: 0000 [#1] SMP 
[    0.129999] Modules linked in:
[    0.129999] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.0.0-00114-g0215155 #8
[    0.129999] task: c0030000 ti: c0038000 task.ti: c0038000
[    0.129999] EIP: 0060:[<c10da708>] EFLAGS: 00010206 CPU: 0
[    0.129999] EIP is at irq_work_run_list+0x68/0x70
[    0.129999] EAX: 00000200 EBX: c0030000 ECX: d42cae0c EDX: 00000000
[    0.129999] ESI: 00000000 EDI: 00000000 EBP: c0039cd0 ESP: c0039ccc
[    0.129999]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[    0.129999] CR0: 80050033 CR2: ffffffff CR3: 01e33000 CR4: 000406d0
[    0.129999] Stack:
[    0.129999]  c10da8b6 c0039ce0 c10a7806 d42c8700 07bfa473 c0039cf8 c10b56e8 00000000
[    0.129999]  00000001 00000000 c10b596f c0039d14 c10b596f c0030000 00000000 d42c8700
[    0.129999]  00000000 00000246 c0039d28 c10304ff 00000246 c0039d28 00000000 c0039d34
[    0.129999] Call Trace:
[    0.129999]  [<c10da8b6>] ? irq_work_tick+0x36/0x40
[    0.129999]  [<c10a7806>] update_process_times+0x46/0x60
[    0.129999]  [<c10b56e8>] tick_periodic+0x28/0xc0
[    0.129999]  [<c10b596f>] ? tick_handle_periodic+0x1f/0x70
[    0.129999]  [<c10b596f>] tick_handle_periodic+0x1f/0x70
[    0.129999]  [<c10304ff>] local_apic_timer_interrupt+0x2f/0x60
[    0.129999]  [<c10308ce>] smp_apic_timer_interrupt+0x2e/0x50
[    0.129999]  [<c185464d>] apic_timer_interrupt+0x31/0x38
[    0.129999]  [<c108df87>] ? lock_acquire+0x87/0xa0
[    0.129999]  [<c1155341>] ? new_inode_pseudo+0x21/0x50
[    0.129999]  [<c18532b9>] _raw_spin_lock+0x39/0x50
[    0.129999]  [<c1155341>] ? new_inode_pseudo+0x21/0x50
[    0.129999]  [<c1155341>] new_inode_pseudo+0x21/0x50
[    0.129999]  [<c1155382>] new_inode+0x12/0x30
[    0.129999]  [<c1160233>] simple_fill_super+0x33/0x1b0
[    0.129999]  [<c113bc00>] ? get_anon_bdev+0xe0/0xe0
[    0.129999]  [<c11d3332>] fill_super+0x12/0x20
[    0.129999]  [<c113d21f>] mount_single+0x7f/0xa0
[    0.129999]  [<c11d3315>] get_sb+0x15/0x20
[    0.129999]  [<c11d3320>] ? get_sb+0x20/0x20
[    0.129999]  [<c113d2e7>] mount_fs+0x37/0x180
[    0.129999]  [<c1085667>] ? __init_waitqueue_head+0x37/0x50
[    0.129999]  [<c1158d60>] ? mntput+0x30/0x30
[    0.129999]  [<c1158187>] vfs_kern_mount+0x47/0x140
[    0.129999]  [<c1160420>] simple_pin_fs+0x70/0x90
[    0.129999]  [<c11d339e>] securityfs_create_file+0x5e/0x1e0
[    0.129999]  [<c1ddccbc>] ? aa_destroy_aafs+0xf/0xf
[    0.129999]  [<c11d353f>] securityfs_create_dir+0x1f/0x30
[    0.129999]  [<c1ddcc35>] aafs_create_dir+0xf/0x87
[    0.129999]  [<c1ddccbc>] ? aa_destroy_aafs+0xf/0xf
[    0.129999]  [<c1ddcd09>] aa_create_aafs+0x4d/0x9f
[    0.129999]  [<c1000486>] do_one_initcall+0xc6/0x210
[    0.129999]  [<c1ddccbc>] ? aa_destroy_aafs+0xf/0xf
[    0.129999]  [<c1dbd4f3>] ? repair_env_string+0x12/0x54
[    0.129999]  [<c1dbdc98>] kernel_init_freeable+0x17d/0x1fa
[    0.129999]  [<c1846aeb>] kernel_init+0xb/0xe0
[    0.129999]  [<c1853da1>] ret_from_kernel_thread+0x21/0x30
[    0.129999]  [<c1846ae0>] ? rest_init+0xb0/0xb0
[    0.129999] Code: 89 4d f0 89 f9 87 4b fc ff 53 04 89 f2 89 f8 83 e2 fc 3e 0f b1 53 fc 8b 5d f0 85 db 75 d5 58 5b 5e 5f 5d c3 8d b4 26 00 00 00 00 <0f> 0b 8d b6 00 00 00 00 55 b8 10 5e e2 c1 89 e5 64 03 05 cc 20
[    0.129999] EIP: [<c10da708>] irq_work_run_list+0x68/0x70 SS:ESP 0068:c0039ccc
[    0.151522] ---[ end trace c72def77197feb46 ]---
[    0.151895] Kernel panic - not syncing: Fatal exception in interrupt

Thanks,
Ying Huang