Greetings,

FYI, the below debug patch triggers a warning on cpuidle code path

git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

commit 3d693a5127e79e79da7c34dc0c776bc620697ce5
Author:     Andrew Morton <akpm@linux-foundation.org>
AuthorDate: Mon Mar 17 11:23:56 2014 +1100
Commit:     Stephen Rothwell <sfr@canb.auug.org.au>
CommitDate: Mon Mar 17 11:23:56 2014 +1100

    mm-vmalloc-avoid-soft-lockup-warnings-when-vunmaping-large-ranges-fix
    
    add a might_sleep() to catch atomic callers more promptly
    
    Cc: David Vrabel <david.vrabel@citrix.com>
    Cc: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>


[   26.028136] BUG: sleeping function called from invalid context at /c/kernel-tests/src/lkp/mm/vmalloc.c:74
[   26.040078] in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/0
[   26.040080] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.14.0-rc6-next-20140317 #1
[   26.040081] Hardware name: Intel Corporation S5520UR/S5520UR, BIOS S5500.86B.01.00.0050.050620101605 05/06/2010
[   26.040083]  0000000000000000 ffff8801e9c06d00 ffffffff81a3ae8a ffffc90001870000
[   26.040084]  ffff8801e9c06d10 ffffffff81101256 ffff8801e9c06d88 ffffffff811b1540
[   26.040089]  ffffc90001870fff ffffc90001870fff 0000000000000001 000037008ddb0000
[   26.040089] Call Trace:
[   26.040094]  <NMI>  [<ffffffff81a3ae8a>] dump_stack+0x4d/0x66
[   26.040098]  [<ffffffff81101256>] __might_sleep+0x10a/0x10c
[   26.040101]  [<ffffffff811b1540>] vunmap_page_range+0x143/0x2b2
[   26.040102]  [<ffffffff811b16c0>] unmap_kernel_range_noflush+0x11/0x13
[   26.040105]  [<ffffffff8156f578>] ghes_copy_tofrom_phys+0x11f/0x189
[   26.040106]  [<ffffffff8156f66a>] ghes_read_estatus+0x88/0x134
[   26.040108]  [<ffffffff81570379>] ghes_notify_nmi+0x53/0x1e7
[   26.040110]  [<ffffffff81a4370c>] nmi_handle.isra.4+0x68/0x113
[   26.040112]  [<ffffffff81a43e51>] ? perf_ibs_nmi_handler+0x3d/0x3d
[   26.040113]  [<ffffffff81a43867>] do_nmi+0xb0/0x2de
[   26.040114]  [<ffffffff81a42e91>] end_repeat_nmi+0x1e/0x2e
[   26.040118]  [<ffffffff81066ac0>] ? native_write_msr_safe+0xa/0xe
[   26.040119]  [<ffffffff81066ac0>] ? native_write_msr_safe+0xa/0xe
[   26.040120]  [<ffffffff81066ac0>] ? native_write_msr_safe+0xa/0xe
[   26.040124]  <<EOE>>  <IRQ>  [<ffffffff8104e597>] intel_pmu_enable_all+0x4c/0x9b
[   26.040125]  [<ffffffff8104e607>] intel_pmu_nhm_enable_all+0x21/0x152
[   26.040127]  [<ffffffff81049b00>] x86_pmu_enable+0x134/0x273
[   26.040129]  [<ffffffff81176942>] perf_pmu_enable+0x22/0x24
[   26.040130]  [<ffffffff81048268>] x86_pmu_commit_txn+0x7b/0x98
[   26.040132]  [<ffffffff81112a66>] ? __wake_up+0x44/0x4b
[   26.040135]  [<ffffffff81579c81>] ? tty_wakeup+0x5b/0x60
[   26.040137]  [<ffffffff81593d02>] ? uart_write_wakeup+0x20/0x22
[   26.040139]  [<ffffffff81596c7d>] ? serial8250_tx_chars+0xd9/0x142
[   26.040140]  [<ffffffff81a42396>] ? _raw_spin_unlock_irqrestore+0x25/0x41
[   26.040141]  [<ffffffff81a4220b>] ? _raw_spin_lock_irqsave+0x25/0x56
[   26.040142]  [<ffffffff81a42396>] ? _raw_spin_unlock_irqrestore+0x25/0x41
[   26.040144]  [<ffffffff810fb494>] ? hrtimer_get_next_event+0x83/0x98
[   26.040145]  [<ffffffff81177ad6>] ? event_sched_in+0x133/0x143
[   26.040146]  [<ffffffff81177b79>] group_sched_in+0x93/0x13c
[   26.040149]  [<ffffffff8103edc7>] ? native_sched_clock+0x31/0x93
[   26.040150]  [<ffffffff81178a83>] __perf_event_enable+0x1ad/0x1ea
[   26.040151]  [<ffffffff81175275>] remote_function+0x17/0x40
[   26.040154]  [<ffffffff8113786f>] generic_smp_call_function_single_interrupt+0x74/0xdb
[   26.040156]  [<ffffffff8105bb9e>] smp_call_function_single_interrupt+0x27/0x36
[   26.040158]  [<ffffffff81a4ae32>] call_function_single_interrupt+0x72/0x80
[   26.040161]  <EOI>  [<ffffffff818e7546>] ? cpuidle_enter_state+0x59/0xb5
[   26.040162]  [<ffffffff818e7542>] ? cpuidle_enter_state+0x55/0xb5
[   26.040164]  [<ffffffff818e75ce>] cpuidle_enter+0x17/0x19
[   26.040165]  [<ffffffff81113271>] cpu_startup_entry+0x227/0x3b8
[   26.040167]  [<ffffffff81a2ca43>] rest_init+0x87/0x89
[   26.040169]  [<ffffffff82353dda>] start_kernel+0x401/0x40c
[   26.040170]  [<ffffffff823537e7>] ? repair_env_string+0x58/0x58
[   26.040171]  [<ffffffff82353120>] ? early_idt_handlers+0x120/0x120
[   26.040173]  [<ffffffff823534a2>] x86_64_start_reservations+0x2a/0x2c
[   26.040174]  [<ffffffff823535df>] x86_64_start_kernel+0x13b/0x148
[   26.463198] perf interrupt took too long (2503 > 2500), lowering kernel.perf_event_max_sample_rate to 50000

Thanks,
Fengguang