FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
commit d18bbc215f81710e1eab7120becafa910554d68d ("kernel/printk/printk.c: revert "printk: enable interrupts before calling console_trylock_for_printk()"")


+----------------------------------------------------+------------+------------+
|                                                    | e84f1ab33c | d18bbc215f |
+----------------------------------------------------+------------+------------+
| boot_successes                                     | 0          | 6          |
| boot_failures                                      | 32         | 24         |
| BUG:spinlock_lockup_suspected_on_CPU               | 32         |            |
| INFO:possible_circular_locking_dependency_detected | 32         |            |
| INFO:rcu_preempt_self-detected_stall_on_CPU        | 31         |            |
| RIP:flat_send_IPI_mask                             | 31         |            |
| backtrace:do_sys_open                              | 32         | 7          |
| backtrace:SyS_open                                 | 32         |            |
| backtrace:kernel_init_freeable                     | 32         |            |
| backtrace:print_ICs                                | 32         |            |
| backtrace:setup_default_timer_irq                  | 32         |            |
| backtrace:hpet_time_init                           | 32         |            |
| backtrace:x86_late_time_init                       | 32         |            |
| Out_of_memory:Kill_process                         | 0          | 24         |
| backtrace:compat_SyS_open                          | 0          | 7          |
| backtrace:sock_create                              | 0          | 4          |
| backtrace:SyS_socket                               | 0          | 5          |
| backtrace:compat_SyS_socketcall                    | 0          | 5          |
| page_allocation_failure:order:#,mode               | 0          | 2          |
| backtrace:vmalloc                                  | 0          | 2          |
| backtrace:SyS_init_module                          | 0          | 2          |
| WDT_device_closed_unexpectedly.WDT_will_not_stop   | 0          | 3          |
| backtrace:do_fork                                  | 0          | 4          |
| backtrace:SyS_clone                                | 0          | 3          |
| backtrace:__mm_populate                            | 0          | 4          |
| backtrace:SyS_mlockall                             | 0          | 4          |
| backtrace:compat_SyS_openat                        | 0          | 1          |
| backtrace:sock_alloc_file                          | 0          | 1          |
+----------------------------------------------------+------------+------------+

We found the commit fixed the problem in the parent commit as below (attached as
dmesg_of_the_parent_commit).

[    2.530427] BUG: spinlock lockup suspected on CPU#0, swapper/1
[    2.530427]  lock: serial8250_ports+0x0/0x700, .magic: dead4ead, .owner: swapper/1, .owner_cpu: 0
[    2.530427] CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-rc3-00074-ge84f1ab #16
[    2.530427]  0000000000000000 ffff8800003b7650 ffffffff816d97b8 ffff8800003b7670
[    2.530427]  ffffffff810989a0 ffffffff82dc7d80 00000000a08baba0 ffff8800003b7698
[    2.530427]  ffffffff81098b35 ffffffff82dc7d80 0000000000000046 0000000000000000
[    2.530427] Call Trace:
[    2.530427]  [<ffffffff816d97b8>] dump_stack+0x19/0x1b
[    2.530427]  [<ffffffff810989a0>] spin_dump+0x90/0x95
[    2.530427]  [<ffffffff81098b35>] do_raw_spin_lock+0x108/0x128
[    2.530427]  [<ffffffff816e16ac>] _raw_spin_lock_irqsave+0x4f/0x5b
[    2.530427]  [<ffffffff813ca0ac>] ? serial8250_console_write+0xaf/0x15b
[    2.530427]  [<ffffffff813ca0ac>] serial8250_console_write+0xaf/0x15b
[    2.530427]  [<ffffffff8109d72d>] call_console_drivers+0xc6/0x175
[    2.530427]  [<ffffffff8109e7e8>] console_unlock+0x2e2/0x3ca
[    2.530427]  [<ffffffff8109ed5b>] vprintk_emit+0x48b/0x49f
[    2.530427]  [<ffffffff816d78eb>] printk+0x4f/0x57
[    2.530427]  [<ffffffff816d6f65>] print_circular_bug_header+0x3c/0xd8
[    2.530427]  [<ffffffff816d707f>] print_circular_bug+0x7e/0x2bf
[    2.530427]  [<ffffffff810951fc>] __lock_acquire+0x13dd/0x1a6d
[    2.530427]  [<ffffffff810a0200>] ? irq_alloc_hwirqs+0x95/0x95
[    2.530427]  [<ffffffff81095252>] ? __lock_acquire+0x1433/0x1a6d
[    2.530427]  [<ffffffff81095f8d>] lock_acquire+0xc6/0x1a9
[    2.530427]  [<ffffffff81095f8d>] ? lock_acquire+0xc6/0x1a9
[    2.530427]  [<ffffffff810a02aa>] ? __irq_get_desc_lock+0x8a/0x9a
[    2.530427]  [<ffffffff816e16a4>] _raw_spin_lock_irqsave+0x47/0x5b
[    2.530427]  [<ffffffff810a02aa>] ? __irq_get_desc_lock+0x8a/0x9a
[    2.530427]  [<ffffffff810a02aa>] __irq_get_desc_lock+0x8a/0x9a
[    2.530427]  [<ffffffff810a15c3>] __disable_irq_nosync+0x23/0x56
[    2.530427]  [<ffffffff810a1604>] disable_irq_nosync+0xe/0x10
[    2.530427]  [<ffffffff813cc1c1>] serial8250_startup+0x287/0x771
[    2.530427]  [<ffffffff813c8496>] uart_startup+0x9a/0x1b8
[    2.530427]  [<ffffffff813c8e7e>] uart_open+0x11f/0x164
[    2.530427]  [<ffffffff813b83dd>] tty_open+0x3f9/0x633
[    2.530427]  [<ffffffff81157d10>] chrdev_open+0x135/0x149
[    2.530427]  [<ffffffff81157bdb>] ? cdev_put+0x15/0x15
[    2.530427]  [<ffffffff81151d9a>] do_dentry_open+0x2d7/0x386
[    2.530427]  [<ffffffff81151e99>] finish_open+0x50/0x64
[    2.530427]  [<ffffffff81161d17>] do_last+0x974/0xc2a
[    2.530427]  [<ffffffff8116229c>] path_openat+0x2cf/0x782
[    2.530427]  [<ffffffff8116372e>] do_filp_open+0x4b/0xf1
[    2.530427]  [<ffffffff816e17a9>] ? _raw_spin_unlock+0x47/0x53
[    2.530427]  [<ffffffff81171c00>] ? __alloc_fd+0x155/0x167
[    2.530427]  [<ffffffff81152e15>] do_sys_open+0x166/0x20e
[    2.530427]  [<ffffffff81152e15>] ? do_sys_open+0x166/0x20e
[    2.530427]  [<ffffffff813db22b>] ? random_int_secret_init+0x1a/0x1e
[    2.530427]  [<ffffffff81152edb>] SyS_open+0x1e/0x20
[    2.530427]  [<ffffffff81fed20c>] kernel_init_freeable+0x1ec/0x255
[    2.530427]  [<ffffffff816d48ed>] ? rest_init+0x131/0x131
[    2.530427]  [<ffffffff816d48fb>] kernel_init+0xe/0xda
[    2.530427]  [<ffffffff816e243a>] ret_from_fork+0x7a/0xb0
[    2.530427]  [<ffffffff816d48ed>] ? rest_init+0x131/0x131


Thanks,
Ying Huang