Hi Frederic,

The below warning shows up in

tree:   git://github.com/fweisbec/linux-dynticks.git nohz/printk-v2
head:   e6d30a660d27a17260d2b8ac9e733ca9870f04d4
commit: e6d30a660d27a17260d2b8ac9e733ca9870f04d4 [8/8] printk: Wake up klogd using irq_work

[    0.116059] kvm-stealtime: cpu 1, msr e537540
[    0.120011] smpboot: Total of 2 processors activated (10665.79 BogoMIPS)
[  100.135075] INFO: rcu_preempt detected stalls on CPUs/tasks:
[  100.136047] 
[  100.136726] 
[  100.137443] sending NMI to all CPUs:
[  100.138022] NMI backtrace for cpu 0
[  100.138283] Pid: 0, comm: swapper/0 Not tainted 3.6.0-00008-ge6d30a6 #61 Bochs Bochs
[  100.138283] EIP: 0060:[<4101cbcd>] EFLAGS: 00010046 CPU: 0
[  100.138283] EIP is at default_send_IPI_mask_logical+0x9d/0x120
[  100.138283] EAX: 00000c00 EBX: 03000000 ECX: fffff000 EDX: fffff000
[  100.138283] ESI: 00000002 EDI: 00000002 EBP: 41889ea8 ESP: 41889e8c
[  100.138283]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[  100.138283] CR0: 8005003b CR2: ffffffff CR3: 019a5000 CR4: 00000690
[  100.138283] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  100.138283] DR6: ffff0ff0 DR7: 00000400
[  100.138283] Process swapper/0 (pid: 0, ti=41888000 task=41890e00 task.ti=41888000)
[  100.138283] Stack:
[  100.138283]  00002710 4189bb40 00000001 00000800 00002710 4189bb40 00000001 41889eb8
[  100.138283]  4101cd60 00002710 4189bb40 41889ec8 4101cf61 417cf9ef 4e52de20 41889f00
[  100.138283]  4107ed5a 417dcd90 00000000 000061aa 4e52de20 4189bd04 00000002 00000001
[  100.138283] Call Trace:
[  100.138283]  [<4101cd60>] default_send_IPI_all+0x80/0x90
[  100.138283]  [<4101cf61>] arch_trigger_all_cpu_backtrace+0x41/0x70
[  100.138283]  [<4107ed5a>] rcu_check_callbacks+0x4fa/0x540
[  100.138283]  [<41035426>] update_process_times+0x36/0x70
[  100.138283]  [<41061045>] tick_periodic+0x25/0x70
[  100.138283]  [<410610f8>] tick_handle_periodic+0x18/0x70
[  100.138283]  [<4101bcff>] smp_apic_timer_interrupt+0x4f/0x80
[  100.138283]  [<4164b05d>] apic_timer_interrupt+0x2d/0x34
[  100.138283]  [<410219c0>] ? native_irq_enable+0x10/0x10
[  100.138283]  [<4195007b>] ? memblock_dump.isra.8+0x1d/0x117
[  100.138283]  [<410219c5>] ? native_safe_halt+0x5/0x10
[  100.138283]  [<41009e32>] default_idle+0x32/0x60
[  100.138283]  [<4100a878>] cpu_idle+0x68/0xa0
[  100.138283]  [<415fdb3f>] rest_init+0xab/0xbc
[  100.138283]  [<415fda94>] ? __read_lock_failed+0x14/0x14
[  100.138283]  [<4191396d>] start_kernel+0x32e/0x334
[  100.138283]  [<41913474>] ? repair_env_string+0x51/0x51
[  100.138283]  [<419132a2>] i386_start_kernel+0x78/0x7d
[  100.138283] Code: 00 b3 ff ff f6 c4 10 75 ed c1 e3 18 89 99 10 b3 ff ff 89 f0 09 d0 80 ce 04 83 fe 02 0f 44 c2 8b 15 a4 71 89 41 89 82 00 b3 ff ff <8b> 1d 5c 70 89 41 85 db 74 3e 89 f8 50 9d 8d 74 26 00 83 c4 10
[    0.124078] NMI backtrace for cpu 1
[    0.124078] Pid: 0, comm: swapper/1 Not tainted 3.6.0-00008-ge6d30a6 #61 Bochs Bochs
[    0.124078] EIP: 0060:[<410819ad>] EFLAGS: 00000002 CPU: 1
[    0.124078] EIP is at irq_work_run+0x5d/0x90
[    0.124078] EAX: 41897f0c EBX: 00000000 ECX: 4e537fec EDX: 00000000
[    0.124078] ESI: 41897f10 EDI: 41897f10 EBP: 4c463eec ESP: 4c463ee0
[    0.124078]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[    0.124078] CR0: 8005003b CR2: ffffffff CR3: 019a5000 CR4: 00000690
[    0.124078] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    0.124078] DR6: ffff0ff0 DR7: 00000400
[    0.124078] Process swapper/1 (pid: 0, ti=4c462000 task=4c43e840 task.ti=4c462000)
[    0.124078] Stack:
[    0.124078]  4c43e840 00000000 00000001 4c463f00 4103543b 4e537440 4e537440 00000000
[    0.124078]  4c463f08 41061045 4c463f24 410610f8 00000000 00000001 00000000 4e537440
[    0.124078]  00000000 4c463f3c 4101bcff 4c43e840 419118c0 419118c0 00000001 4c463f80
[    0.124078] Call Trace:
[    0.124078]  [<4103543b>] update_process_times+0x4b/0x70
[    0.124078]  [<41061045>] tick_periodic+0x25/0x70
[    0.124078]  [<410610f8>] tick_handle_periodic+0x18/0x70
[    0.124078]  [<4101bcff>] smp_apic_timer_interrupt+0x4f/0x80
[    0.124078]  [<4164b05d>] apic_timer_interrupt+0x2d/0x34
[    0.124078]  [<410219c0>] ? native_irq_enable+0x10/0x10
[    0.124078]  [<410600d8>] ? alarmtimer_suspend+0xb8/0x1a0
[    0.124078]  [<410219c5>] ? native_safe_halt+0x5/0x10
[    0.124078]  [<41009e32>] default_idle+0x32/0x60
[    0.124078]  [<4100a878>] cpu_idle+0x68/0xa0
[    0.124078]  [<41639a5d>] start_secondary+0x1d4/0x1db
[    0.124078] Code: 89 41 85 c0 74 48 9c 58 8d 74 26 00 89 c2 81 e2 00 02 00 00 75 36 89 d7 87 39 85 ff 74 27 31 db 8d b6 00 00 00 00 8d 47 fc 8b 37 <c7> 47 fc 02 00 00 00 ff 57 04 b8 02 00 00 00 f0 0f b1 5f fc 85
[  100.146845] devtmpfs: initialized
[  100.147970] EVM: security.selinux

Thanks,
Fengguang