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-s... 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