FYI, we noticed the following commit:

commit: b1e955caea7e3ae340ebd5392a7fe4478f64ce1d ("x86/paravirt: Avoid setting IF flag, if not necessary")
url: https://github.com/0day-ci/linux/commits/Waiman-Long/x86-paravirt-Avoid-setting-IF-flag-if-not-necessary/20170207-051507


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-x86_64 -m 320M

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


+----------------------------------------------------------------+------------+------------+
|                                                                | 10b9dd5686 | b1e955caea |
+----------------------------------------------------------------+------------+------------+
| boot_successes                                                 | 2          | 4          |
| boot_failures                                                  | 2          | 4          |
| WARNING:at_arch/x86/include/asm/fpu/internal.h:#fpu__restore   | 2          |            |
| WARNING:at_kernel/locking/lockdep.c:#trace_hardirqs_off_caller | 0          | 4          |
| calltrace:native_smp_prepare_cpus                              | 0          | 4          |
+----------------------------------------------------------------+------------+------------+



[    3.528640] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2760 trace_hardirqs_off_caller+0x108/0x120
[    3.530745] DEBUG_LOCKS_WARN_ON(!irqs_disabled())
[    3.532013] Modules linked in:
[    3.533837] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-rc6-00134-gb1e955c #1
[    3.534833] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[    3.537411]  ffffc9000000bcc8 ffffffff8144e9e3 ffffffff8113d618 ffffc9000000bd28
[    3.539432]  ffffc9000000bd28 0000000000000000 ffffc9000000bd18 ffffffff810ac222
[    3.540000]  0000000000000000 00000ac800000001 0000000000000000 00000000ffff8c25
[    3.540000] Call Trace:
[    3.540000]  [<ffffffff8144e9e3>] dump_stack+0xf1/0x16e
[    3.540000]  [<ffffffff8113d618>] ? trace_hardirqs_off_caller+0x108/0x120
[    3.540000]  [<ffffffff810ac222>] __warn+0x172/0x1a0
[    3.540000]  [<ffffffff810ac361>] warn_slowpath_fmt+0x61/0x80
[    3.540000]  [<ffffffff814644d0>] ? delay_tsc+0x1a0/0x1d0
[    3.540000]  [<ffffffff8113d618>] trace_hardirqs_off_caller+0x108/0x120
[    3.540000]  [<ffffffff8113d64d>] trace_hardirqs_off+0x1d/0x30
[    3.540000]  [<ffffffff82636855>] timer_irq_works+0x9f/0x10f
[    3.540000]  [<ffffffff82636f58>] setup_IO_APIC+0x693/0xee5
[    3.540000]  [<ffffffff81b6cb91>] ? _raw_spin_unlock_irqrestore+0x91/0xf0
[    3.540000]  [<ffffffff81054d43>] ? clear_IO_APIC_pin+0xe3/0x1a0
[    3.540000]  [<ffffffff82634398>] apic_bsp_setup+0x105/0x122
[    3.540000]  [<ffffffff82633422>] native_smp_prepare_cpus+0x4b3/0x55e
[    3.540000]  [<ffffffff8261fbfd>] kernel_init_freeable+0x76/0x2c4
[    3.540000]  [<ffffffff81b54e10>] ? rest_init+0x220/0x220
[    3.540000]  [<ffffffff81b54e26>] kernel_init+0x16/0x1d0
[    3.540000]  [<ffffffff81b6cfaa>] ret_from_fork+0x2a/0x40
[    3.543531] ---[ end trace 14a0f48288b7a69f ]---


To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong