Segmentation fault running Mediawiki

[jowilkin]

I have 2 headless VirtualBox VMs running on a server with host operating system Ubuntu 8.04 server edition and both guests running the same. Host and guests are x86. I set this up maybe a week or two ago and have had both of them seg fault while doing routine editing on a mediawiki wiki. I launch them from the console with the VBoxHeadless command. I'm running the PUEL edition of virtual box with guest additions. This is an academic use so I think I am within the rules of the license.

The console I ran the virtual machines from simply says "segmentation fault" with no other information. Does virtualbox have a log file anywhere? I tried looking in /var/log but cannot find anything. Does it log to one of the system log files? Here is the output

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vbox@di2ag:~$ VBoxHeadless --startvm PrivateWebServer --vrdp=off
VirtualBox Headless Interface 2.2.0
(C) 2008-2009 Sun Microsystems, Inc.
All rights reserved.

Segmentation fault
vbox@di2ag:~$

Is virtualbox not stable enough to run servers? These servers both had extremely low utilization and I am fairly certain that only one person was using them (me) when the seg faults occurred each time. Should I move to vmware products for a server environment? I have been using virtualbox to run Windows XP on my desktop for a while without any real troubles so I thought I would give it a try on my servers, but this is unacceptable stability so far.

[Perryg]

I believe that VBox is stable enough to run a server. I had one running 24/7/365 for about a year and only down for occasional reboot due to software update. In fact this forum is running on it. However that does not solve your problem. First you need to post the pertinent information. Memory, how much is allocated to each machine. Processor information and the like. Kind of hard to figure out the problem without it. Give as much information as you can find.

[jowilkin]

Ok thanks, hope it didn't sound like I was insulting vbox, just wondering what stage it was at in development and if I was using it in an appropriate manner. Is there a log file for virtualbox in /var/log or elsewhere?

Here is the info I can think of now, the 2 virtual machines are configured identically (except for the ports used to connect) so I am only showing the configuration of one of them. I have had one segmentation fault on each now. The first occurred when I was editing a mediawiki page and the second occurred when I was trying to open a pdf stored on a mediawiki page. Let me know if any other information would be helpful:

Host: Dell Poweredge SC1425 with dual core Intel Xeon @ 3GHz, 1GB Ram, and an 80GB 7.2k rpm SATA drive. The host is only used to control the virtual machines.

Guest information:

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vbox@di2ag:/home/jowilkin$ VBoxManage showvminfo PrivateWebServer
VirtualBox Command Line Management Interface Version 2.2.0
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

Name:            PrivateWebServer
Guest OS:        Ubuntu
UUID:            b146ceeb-f961-4506-ba40-34faf6679d72
Config file:     /home/vbox/.VirtualBox/Machines/PrivateWebServer/PrivateWebServer.xml
Memory size:     384MB
VRAM size:       12MB
Boot menu mode:  message and menu
ACPI:            on
IOAPIC:          on
PAE:             off
Time offset:     0 ms
Hardw. virt.ext: on
Nested Paging:   off
VT-x VPID:       off
State:           running (since 2009-04-27T21:18:52.631000000)
Monitor count:   1
3D Acceleration: off
Floppy:          empty
SATA:            disabled
IDE Controller:  PIIX4
Primary master:  /home/vbox/.VirtualBox/Machines/PrivateWebServer/Snapshots/{2ff376f9-294f-477d-b007-9310f4ebb757}.vdi (UUID: 2ff376f9-294f-477d-b007-9310f4ebb757)
DVD:             /usr/share/virtualbox/VBoxGuestAdditions.iso (UUID: 1094743c-52d1-4a19-9719-cbdb3344f27b)
NIC 1:           MAC: 080027E0358E, Attachment: NAT, Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps
NIC 2:           disabled
NIC 3:           disabled
NIC 4:           disabled
NIC 5:           disabled
NIC 6:           disabled
NIC 7:           disabled
NIC 8:           disabled
UART 1:          disabled
UART 2:          disabled
Audio:           disabled (Driver: Unknown, Controller: Unknown)
Clipboard Mode:  Bidirectional
Video mode:      720x400x0
VRDP:            disabled
USB:             disabled

USB Device Filters:

<none>

Available remote USB devices:

<none>

Currently Attached USB Devices:

<none>

Shared folders:  <none>

VRDP Connection:    not active
Clients so far:     0

Guest:

Statistics update:                   disabled

Snapshots:

   Name: Initial (UUID: 41f3d945-c3cc-4b0e-ba30-5b858dace70b)

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vbox@di2ag:/home/jowilkin$ VBoxManage getextradata PrivateWebServer enumerate
VirtualBox Command Line Management Interface Version 2.2.0
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

Key: GUI/LastCloseAction, Value: powerOff
Key: GUI/LastWindowPostion, Value: 1286,47,720,452
Key: GUI/Fullscreen, Value: off
Key: GUI/Seamless, Value: off
Key: GUI/AutoresizeGuest, Value: on
Key: GUI/SaveMountedAtRuntime, Value: yes
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/HostPort, Value: 4444
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/GuestPort, Value: 22
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/Protocol, Value: TCP
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssl/HostPort, Value: 4443
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssl/GuestPort, Value: 443
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssl/Protocol, Value: TCP

With both machines running, here is what the host says about resources:

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vbox@di2ag:/home/jowilkin$ free -m
             total       used       free     shared    buffers     cached
Mem:          1010        995         15          0         19         81
-/+ buffers/cache:        894        116
Swap:         2957        688       2268

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top - 20:16:29 up 15 days, 19:00,  1 user,  load average: 0.39, 0.14, 0.04
Tasks:  97 total,   1 running,  96 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   1034984k total,  1019452k used,    15532k free,    20316k buffers
Swap:  3028212k total,   704880k used,  2323332k free,    83524k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                         
19105 vbox      20   0  402m 363m  26m S    1 35.9  77:57.03 VBoxHeadless                    
21105 vbox      20   0  310m 295m  29m S    1 29.2   2:14.77 VBoxHeadless

[jowilkin]

Here is some more cpu info:

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vbox@di2ag:/home/jowilkin$ cat /proc/cpuinfo
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	: Intel(R) Xeon(TM) CPU 3.00GHz
stepping	: 3
cpu MHz		: 3000.183
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips	: 6003.88
clflush size	: 64

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	: Intel(R) Xeon(TM) CPU 3.00GHz
stepping	: 3
cpu MHz		: 3000.183
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips	: 6000.29
clflush size	: 64

[Perryg]

Thank you for the additional information.

The first thing that I see is you are running out of memory. You have set the guests at 384 each and you must take into account the amount of memory the host and VBox is using. 1 gig just does not seem like enough to me. Try setting the memory to 256 and see if that will free up enough system resource. There comes a point where something has to give.

You log files should be stored in /home/vbox/.VirtualBox/machine/

Let me know if this helps or not.

[jowilkin]

Ok thanks, but it seems like if I run out of physical ram that swap should just kick in. This should slow things down a lot, but not cause a seg fault. Does virtualbox not deal well with swap?

I will try scaling back the virtual machine memory on each and see if it helps.

[Perryg]

Actually it is not VB that I am concerned with at this point. I looked at your information and the swap and mem. were off the chart.
I am still researching the rest but this give you a starting place to figure where the problem really is. If you determine this is a problem then you will need to start a ticket with VB, but let's do the ground work first.

[Perryg]

I see that there are a lot of problems with the mediawiki as well causing seg faults put this in Google and have a look. segmentation fault using mediawiki
As well as Ubuntu put this in Google as well segmentation fault using Ubuntu.
So this could be a little more time consuming to figure out but let's try the obvious first.

[jowilkin]

I upgraded to 3gb of ram, what would be a safe amount to give to each guest? 1gb each and 1 for the host?

[Perryg]

Sounds like it. Just keep an eye on things and see if you can see anything in the VBox logs.
Are you running the host with or without X?
If you are using a desktop on the host you can find the log in the VBox GUI under machine.

[jowilkin]

I'm running the server without X, it's locked up in a server room that is quite unpleasant to work in so I go in there as infrequently as possible. It's ubuntu server edition which doesn't come with a desktop environment.

I found the logs in the place you recommended, I know I've seen them there before but just forgot about it. Makes sense they wouldn't be in /var/log since vbox tries to run in userland and /var/log requires root access. I can't find anything in the logs about the seg fault, but will keep looking around.

Edit: Actually I think X is installed but not a desktop environment. I can see the vbox gui by using ssh X tunneling, which I've used in the past, but prefer to learn how to do everything with the CLI.

Oh and what is the time shown on the left hand side of the log? Time since VM started? It seems like system time might be more useful, I'm having a hard time ascertaining which point in the log corresponds to the time that vbox crashed.

[Perryg]

OK sounds like you have a plan now. Just watch and see if you encounter any more problems.
Have a great evening.

[jowilkin]

Thanks for your help.

Edit: I believe I found the place in the logs that would correspond to the crash and there is nothing there. I'll report back if I have another seg fault.

[jowilkin]

Extra memory didn't solve it. It seg faulted again today.

Any ideas?

Seems to me this is a virtual box bug no matter how you look at it. Even if mediawiki is somehow causing a seg fault in the guest, it should not cause the entire guest to crash. Maybe it could cause something like Apache to crash in the guest, but it shouldn't bring down the entire guest.

[jowilkin]

Anyone?

Should I file a bug report? What information would be useful in debugging if I do file a report?