NMI watchdog: BUG: soft lockup during KVM guest migration test suite

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Hello Canonical.

We would like the changes in Commit 8117ac6a6c2f pulled into the Ubuntu 16.10 stream to address the following issue:

== Comment: #0 - Balamuruhan S - 2016-09-23 08:48:52 ==
---Problem Description---

Softlock up and call trace observed from libvirtd during guest migration test suite

---uname output---

# uname -a Linux ltc-hab1 4.8.0-11-generic #12-Ubuntu SMP Sat Sep 17 19:58:16 UTC 2016 ppc64le ppc64le ppc64le GNU/Linux

---System Hang---
 NMI watchdog: BUG: soft lockup - CPU#24 stuck for 22s! [libvirtd:50800]
 message is continuous and recovered the machine with reboot

84050.059159] INFO: rcu_sched self-detected stall on CPU
[84050.059339] 24-...: (5659 ticks this GP) idle=fa5/140000000000001/0 softirq=549845/555507 fqs=2176
[84050.059453] (t=5250 jiffies g=690268 c=690267 q=484)
[84055.126993] NMI watchdog: BUG: soft lockup - CPU#24 stuck for 22s! [libvirtd:50800]
[84104.509395] INFO: rcu_sched self-detected stall on CPU
[84104.509591] 24-...: (5659 ticks this GP) idle=5df/140000000000001/0 softirq=562249/562249 fqs=2364
[84104.509820] (t=5250 jiffies g=690387 c=690386 q=351)
[84107.125310] NMI watchdog: BUG: soft lockup - CPU#24 stuck for 22s! [virsh:56627]
[84163.387536] INFO: rcu_sched self-detected stall on CPU
[84163.387716] 24-...: (5250 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=2354
[84163.387960] (t=5251 jiffies g=690488 c=690487 q=297)
[84167.123420] NMI watchdog: BUG: soft lockup - CPU#24 stuck for 22s! [virsh:56633]
[84226.401597] INFO: rcu_sched self-detected stall on CPU
[84226.401769] 24-...: (21004 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=9697
[84226.402012] (t=21005 jiffies g=690488 c=690487 q=1145)
[84289.415706] INFO: rcu_sched self-detected stall on CPU
[84289.415879] 24-...: (36758 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=16889
[84289.416137] (t=36759 jiffies g=690488 c=690487 q=15499)
[84352.429857] INFO: rcu_sched self-detected stall on CPU
[84352.430038] 24-...: (52512 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=23975
[84352.430269] (t=52513 jiffies g=690488 c=690487 q=16027)
[84415.444044] INFO: rcu_sched self-detected stall on CPU
[84415.444222] 24-...: (68266 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=31005
[84415.444434] (t=68267 jiffies g=690488 c=690487 q=16554)
[84478.458262] INFO: rcu_sched self-detected stall on CPU
[84478.458421] 24-...: (84020 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=38023
[84478.458677] (t=84021 jiffies g=690488 c=690487 q=17030)
[84541.472510] INFO: rcu_sched self-detected stall on CPU
[84541.472680] 24-...: (99774 ticks this GP) idle=f69/140000000000002/0 softirq=562274/562274 fqs=45068
[84541.472939] (t=99775 jiffies g=690488 c=690487 q=17512)
[84604.486783] INFO: rcu_sched self-detected stall on CPU

Thanks.

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[Tim Gardner (timg-tpi)]

I am confused. Commit 8117ac6a6c2fa0f847ff6a21a1f32c8d2c8501d0 ('powerpc/powernv: Switch off MMU before entering nap/sleep/rvwinkle mode') has been in the kernel for awhile.

git describe --contains 8117ac6a6c2f
v3.19-rc1~22^2~6

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------- Comment From <email address hidden> 2016-11-08 10:54 EDT-------
(In reply to comment #14)
> I am confused. Commit 8117ac6a6c2fa0f847ff6a21a1f32c8d2c8501d0
> ('powerpc/powernv: Switch off MMU before entering nap/sleep/rvwinkle mode')
> has been in the kernel for awhile.
>
> git describe --contains 8117ac6a6c2f
> v3.19-rc1~22^2~6

Sorry. My error in grabbing the wrong commit for my query. It's the update fix for that earlier commit that we are looking for.

https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=56c46222af0d09149fadec2a3ce9d4889de01cc6

[Tim Gardner (timg-tpi)]

This bug is a duplicate of http://bugs.launchpad.net/bugs/1636330

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------- Comment From <email address hidden> 2016-11-11 11:23 EDT-------
*** This bug has been marked as a duplicate of bug 132390 ***