FYI, we noticed the following commit (built with gcc-4.9):

commit: fe7e1ef5c1044f3ef122b877b078a47e74360dea ("locking/lockdep: Complain if a lock object has no name")
https://github.com/bvanassche/linux for-next

in testcase: trinity
with following parameters:

	runtime: 300s

test-description: Trinity is a linux system call fuzz tester.
test-url: http://codemonkey.org.uk/projects/trinity/


on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 512M

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+----------------------------------------------------------+------------+------------+
|                                                          | 5a5c736d38 | fe7e1ef5c1 |
+----------------------------------------------------------+------------+------------+
| boot_successes                                           | 4          | 0          |
| boot_failures                                            | 0          | 10         |
| WARNING:at_kernel/locking/lockdep.c:#register_lock_class | 0          | 10         |
| EIP:register_lock_class                                  | 0          | 10         |
| EIP:_raw_spin_unlock_irqrestore                          | 0          | 10         |
+----------------------------------------------------------+------------+------------+



[    3.352301] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:749 register_lock_class+0x290/0x540
[    3.372139] Modules linked in:
[    3.377973] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0-rc4-00113-gfe7e1ef #1
[    3.392870] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[    3.409495] EIP: register_lock_class+0x290/0x540
[    3.418406] Code: 68 78 18 9c c1 e8 bb 2c 01 00 68 a0 18 9c c1 e8 b1 2c 01 00 e8 bb cc 66 00 8b 06 83 c4 0c e9 28 fe ff ff 8d b4 26 00 00 00 00 <0f> 0b e9 8f fd ff ff e8 d4 82 22 00 85 c0 74 20 8b 0d 1c 81 b8 c1
[    3.453446] EAX: 00000000 EBX: c1a8ac80 ECX: 00000000 EDX: 00000000
[    3.465266] ESI: dd2d4dfc EDI: 00000000 EBP: dcc39e3c ESP: dcc39e0c
[    3.477580] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210046
[    3.489899] CR0: 80050033 CR2: ffffffff CR3: 01da6000 CR4: 00000690
[    3.501403] Call Trace:
[    3.505909]  <IRQ>
[    3.510025]  __lock_acquire+0x5a/0x1580
[    3.517802]  ? mark_lock+0x44b/0x5e0
[    3.524898]  ? __lock_acquire+0xd6b/0x1580
[    3.532707]  ? pvclock_clocksource_read+0xae/0x1c0
[    3.542397]  lock_acquire+0x82/0x170
[    3.549520]  ? scheduler_tick+0x46/0x130
[    3.557632]  update_rq_clock+0xbe/0x230
[    3.565400]  ? scheduler_tick+0x46/0x130
[    3.576551]  ? prandom_u32+0x1b/0x30
[    3.584813]  scheduler_tick+0x46/0x130
[    3.591975]  update_process_times+0x36/0x40
[    3.599822]  tick_periodic+0x35/0xc0
[    3.606977]  tick_handle_periodic+0x1d/0x70
[    3.615298]  timer_interrupt+0xd/0x20
[    3.623461]  __handle_irq_event_percpu+0x75/0x410
[    3.632593]  handle_irq_event_percpu+0x26/0x60
[    3.640826]  handle_irq_event+0x29/0x50
[    3.647859]  ? irq_set_chained_handler_and_data+0x70/0x70
[    3.657327]  handle_level_irq+0x7a/0x110
[    3.664393]  handle_irq+0x121/0x160
[    3.671878]  </IRQ>
[    3.676245]  do_IRQ+0x48/0x110
[    3.682343]  common_interrupt+0xec/0x100
[    3.690738] EIP: _raw_spin_unlock_irqrestore+0x2c/0x50
[    3.701138] Code: e5 56 53 89 c6 89 d3 8d 40 10 8b 4d 04 ba 01 00 00 00 e8 97 cb 96 ff 89 f0 e8 10 1d 97 ff f6 c7 02 74 1b e8 e6 14 9e ff 53 9d <64> ff 0d d0 57 c5 c1 5b 5e 5d c3 89 f6 8d bc 27 00 00 00 00 53 9d
[    3.739514] EAX: c1a8ac80 EBX: 00200246 ECX: 0001056c EDX: 00000001
[    3.751830] ESI: dcc20464 EDI: c1a9b440 EBP: c1a83f18 ESP: c1a83f10
[    3.764572] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200246
[    3.779245]  ? tracing_release+0x11b/0x190
[    3.787741]  ? kmsg_dump_get_buffer+0x48/0x3a0
[    3.796330]  __setup_irq+0x42b/0x6f0
[    3.803196]  setup_irq+0x70/0xd0
[    3.809035]  hpet_time_init+0x1d/0x2e
[    3.815808]  x86_late_time_init+0x9/0x16
[    3.823388]  start_kernel+0x414/0x491
[    3.830092]  i386_start_kernel+0x8f/0x93
[    3.837451]  startup_32_smp+0x15f/0x170
[    3.845072] irq event stamp: 3500
[    3.853797] hardirqs last  enabled at (3497): [<c1767e8a>] _raw_spin_unlock_irqrestore+0x2a/0x50
[    3.868808] hardirqs last disabled at (3498): [<c100167d>] trace_hardirqs_off_thunk+0xc/0x1f
[    3.886173] softirqs last  enabled at (3500): [<c108001c>] _local_bh_enable+0x4c/0x70
[    3.900372] softirqs last disabled at (3499): [<c1080d00>] irq_enter+0x50/0x70
[    3.915483] ---[ end trace 11ad95b04038b91f ]---


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp