FYI, we noticed the following commit (built with gcc-7):

commit: b648360016fd691bcb1128a6b7fa2473b3a53ed3 ("tracing: Improve design of preemptirq tracepoints and its users")
url: https://github.com/0day-ci/linux/commits/Joel-Fernandes/tracing-Improve-design-of-preemptirq-tracepoints-and-its-users/20180316-012211


in testcase: boot

on test machine: qemu-system-i386 -enable-kvm -m 256M

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


+--------------------------------------------------+------------+------------+
|                                                  | 3266b5bd97 | b648360016 |
+--------------------------------------------------+------------+------------+
| boot_successes                                   | 8          | 0          |
| boot_failures                                    | 0          | 8          |
| WARNING:at_kernel/locking/lockdep.c:#check_flags | 0          | 8          |
| EIP:check_flags                                  | 0          | 8          |
+--------------------------------------------------+------------+------------+



[    0.004000] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3826 check_flags+0x8f/0x13e
[    0.004000] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3826 check_flags+0x8f/0x13e
[    0.004000] Modules linked in:
[    0.004000] Modules linked in:
[    0.004000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc4-00340-gb648360 #1
[    0.004000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc4-00340-gb648360 #1
[    0.004000] EIP: check_flags+0x8f/0x13e
[    0.004000] EIP: check_flags+0x8f/0x13e
[    0.004000] EFLAGS: 00210012 CPU: 0
[    0.004000] EFLAGS: 00210012 CPU: 0
[    0.004000] EAX: 0000002f EBX: 4c4e78c0 ECX: 00000000 EDX: 00000000
[    0.004000] EAX: 0000002f EBX: 4c4e78c0 ECX: 00000000 EDX: 00000000
[    0.004000] ESI: 4c4fbbd0 EDI: 00000000 EBP: 4c4e1f08 ESP: 4c4e1f00
[    0.004000] ESI: 4c4fbbd0 EDI: 00000000 EBP: 4c4e1f08 ESP: 4c4e1f00
[    0.004000]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[    0.004000]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[    0.004000] CR0: 80050033 CR2: ffffffff CR3: 0ca02000 CR4: 00000690
[    0.004000] CR0: 80050033 CR2: ffffffff CR3: 0ca02000 CR4: 00000690
[    0.004000] Call Trace:
[    0.004000] Call Trace:
[    0.004000]  ? lock_acquire+0x54/0x1b6
[    0.004000]  ? lock_acquire+0x54/0x1b6
[    0.004000]  ? console_lock+0x35/0x6e
[    0.004000]  ? console_lock+0x35/0x6e
[    0.004000]  ? register_console+0x3ce/0x6b9
[    0.004000]  ? register_console+0x3ce/0x6b9
[    0.004000]  ? register_console+0x3ce/0x6b9
[    0.004000]  ? register_console+0x3ce/0x6b9
[    0.004000]  ? native_irq_disable+0x6/0x6
[    0.004000]  ? native_irq_disable+0x6/0x6
[    0.004000]  ? univ8250_console_init+0x32/0x3c
[    0.004000]  ? univ8250_console_init+0x32/0x3c
[    0.004000]  ? console_init+0x17/0x22
[    0.004000]  ? console_init+0x17/0x22
[    0.004000]  ? start_kernel+0x481/0x5e4
[    0.004000]  ? start_kernel+0x481/0x5e4
[    0.004000]  ? i386_start_kernel+0xaa/0xae
[    0.004000]  ? i386_start_kernel+0xaa/0xae
[    0.004000]  ? startup_32_smp+0x164/0x168
[    0.004000]  ? startup_32_smp+0x164/0x168
[    0.004000] Code: 4c 83 b8 a8 04 00 00 00 75 30 e8 0e b1 56 00 85 c0 74 1c 83 3d 00 bd 21 4d 00 75 13 68 2a 4a 3c 4c 68 ad 21 3b 4c e8 0e f6 f8 ff <0f> 0b 58 5a 68 45 4a 3c 4c e8 65 2c 01 00 59 64 8b 15 4c d7 9e
[    0.004000] Code: 4c 83 b8 a8 04 00 00 00 75 30 e8 0e b1 56 00 85 c0 74 1c 83 3d 00 bd 21 4d 00 75 13 68 2a 4a 3c 4c 68 ad 21 3b 4c e8 0e f6 f8 ff <0f> 0b 58 5a 68 45 4a 3c 4c e8 65 2c 01 00 59 64 8b 15 4c d7 9e
[    0.004000] ---[ end trace 49e3ccf384119f2e ]---


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