Ubuntu: BUG: soft lockup – CPU#0 stuck for 11s! | Comments (6)
Posted in Code, Linux/Unix on 20th August 2008, 2:51 pm by Stuart
So this post falls neatly under the “watching paint dry” category, so if you’re susceptible to rage induced by reading terminally dull posts avert your eyes now.
I’ve been having some interesting issues with VMs running on VMware server of late. Basically the problem involved kernel panics and the appearance of lots of messages in the syslog that look like this:
[19133.298838] BUG: soft lockup - CPU#1 stuck for 11s! [swapper:0]
[19133.298929]
[19133.298932] Pid: 0, comm: swapper Not tainted (2.6.24-16-server #1)
[19133.298936] EIP: 0060:[native_safe_halt+0x2/0x10] EFLAGS: 00000246 CPU: 1
[19133.298942] EIP is at native_safe_halt+0x2/0x10
[19133.298945] EAX: 00000000 EBX: 00000001 ECX: c0106f40 EDX: cdde4000
[19133.298949] ESI: c0495004 EDI: c049b300 EBP: 00000000 ESP: cdde5fa4
[19133.298952] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[19133.298956] CR0: 8005003b CR2: b7f51828 CR3: 0049c000 CR4: 000006b0
[19133.298960] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[19133.298963] DR6: ffff0ff0 DR7: 00000400
[19133.298966] [default_idle+0x3c/0x60] default_idle+0x3c/0x60
[19133.298972] [cpu_idle+0x73/0xd0] cpu_idle+0x73/0xd0
[19133.298987] =======================
[19133.302433] BUG: soft lockup - CPU#1 stuck for 11s! [swapper:0]
I found this bug which noted that adding the kernel parameter “noapic” would resolve the issue. In case you’re wondering at this point what apic is (well you read this far), the this wiki page details it quite nicely: http://wiki.linuxquestions.org/wiki/APIC
This worked for two out of the three vms but the third was still showing the same error messages.
I thought I’d update to the newest verison of the 2.6.24.19-server kernel
Following a quick:
sudo apt-get update
sudo apt-get upgrade
Followed by a reboot to pick up the newest edition of the 2.6.24.19-server kernel the messages have gone away.
What’s not clear to me is what is the cause of these issues as they seemed to appear out of no where though I suspect they may have been related to the cpufrequency changes to prevent time drift.

[...] Well I started to do some digging. First I just googled the error message and came up with this post. [...]
I seem to have run into this bug also however running 2.6.24-19-generic on vmware server 1.0.8. Looks like i’ll give noapic a try and go from there
Not sure if this is relevant:
Apart from this I also experienced:
My machine appeared to have locked-up – every 15 to 20 seconds it would unfreeze though… then I could do things for a few seconds (i.e. change from X11 GUI to console (terminal)), then it would freeze again.
I was running GKrellM (http://gkrellm.net), and CPU usage was NIL on Core1, and high on Core0.
Ambient temperature was around 30 Degrees Celsius, and Humidity was approaching 100%.
CPU according to the BIOS was ~62 Degrees Celsius.
From what I can gather on Intel’s website, the CPU hardware has HW thermal protection:
I believe this may be what is causing the syslog messages?
HTH.
I’ve been experiencing the same issues with Ubuntu under Xen at VPS.NET. I run ubuntu (hardy) on VMWare ESXi in production at work with no issues. I see this post is from January. Have the VMs remained stable since this update?
[...] and found that it may be an Ubuntu thing. Seems that other people have had the same problem with Ubuntu under VMWare. Stuart suggested a fix which worked for 3 out of 4 of his VMs. The ubuntu forum he links to [...]
I’ve been having this problem using turnkey linux drupal appliance (Ubuntu 8.04 LTS) on VPS.net . It seems to happen every 12 hours or so.
I tried apt-get update / upgrade, but the problem didn’t go away. Trying with noapic added to grub now, I’ll post my findings here.
Thanks for the post, it’s a big help.