'Interrupted system call' booting domains

'Interrupted system call' booting domains

[Tom Hibbert]

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Hi all
 
I am a recent (as of this weekend) convert to Xen and I have to say I am
very, very impressed!
 
I am now planning a project to create a default Xen domain-0
installation CD based on Debian, providing an easy to use system for
creating
additional domains at install time.
 
But first I need to iron out some issues with my personal Xen
installation.
 
When I create the domains (xm create -f /etc/xen/auto/dom1 etc) I
sometimes get the error 'Interrupted system call'. Interrogating the
xend-debug.log file yeilds the following which is the only discernable
error:
 
ioctl: LOOP_SET_FD: Device or resource error
 
This would say to me that I am using all 8 loop devices. I upped the
max_loop parameter on boot to 255, but it hasnt fixed the issue.
 
As I said before I only get this error sometimes. If i repeat the xm
create command, it usually starts the domain the second time. The
problem with this is that I cant rely on the domains to get
automatically restarted after reboot. 
 
Here is the complete output from xend-debug.log if that helps.
 
network start bridge=xen-br0 netdev=eth0 antispoof=no
VIRTUAL MEMORY ARRANGEMENT:
 Loaded kernel: c0100000->c038ad18
 Init. ramdisk: c038b000->c038b000
 Phys-Mach map: c038b000->c039b000
 Page tables:   c039b000->c039e000
 Start info:    c039e000->c039f000
 Boot stack:    c039f000->c03a0000
 TOTAL:         c0000000->c0800000
 ENTRY ADDRESS: c0100000
ioctl: LOOP_SET_FD: Device or resource busy
op_create> Deferred Exception creating domain: [Errno 4] Interrupted
system call
Traceback (most recent call last):
  File "/usr/lib/python2.3/site-packages/twisted/internet/defer.py",
line 338, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
  File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py",
line 958, in <lambda>
    d.addCallback(lambda x: self.create_devices())
  File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py",
line 785, in create_devices
    v = dev_handler(self, dev, dev_index)
  File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py",
line 1085, in vm_dev_vbd
    defer = ctrl.attachDevice(idx, val, recreate=recreate)
  File "/usr/lib/python2.3/site-packages/xen/xend/server/blkif.py", line
495, in attachDevice
    d = dev.attach()
  File "/usr/lib/python2.3/site-packages/xen/xend/server/blkif.py", line
314, in attach
    node = Blkctl.block('bind', self.type, self.params)
  File "/usr/lib/python2.3/site-packages/xen/xend/Blkctl.py", line 40,
in block
    output = out.readline()
IOError: [Errno 4] Interrupted system call

Hopefully I am doing something dumb somewhere and there is a quick fix
so I can get on to setting up my project page :)
 
Thanks in advance
 
Tom

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Re: 'Interrupted system call' booting domains

[Mike Wray]

Tom Hibbert wrote:
> Hi all
>  
> I am a recent (as of this weekend) convert to Xen and I have to say I am 
> very, very impressed!
>  
> I am now planning a project to create a default Xen domain-0 
> installation CD based on Debian, providing an easy to use system for 
> creating
> additional domains at install time.
>  
> But first I need to iron out some issues with my personal Xen installation.
>  
> When I create the domains (xm create -f /etc/xen/auto/dom1 etc) I 
> sometimes get the error 'Interrupted system call'. Interrogating the 
> xend-debug.log file yeilds the following which is the only discernable 
> error:
>  
> ioctl: LOOP_SET_FD: Device or resource error
>  
> This would say to me that I am using all 8 loop devices. I upped the 
> max_loop parameter on boot to 255, but it hasnt fixed the issue.

Could you post the config file you are using to start the domain
when you get the problem? It also might be worth running losetup to
have a look at the state of the /dev/loop* devices:

for f in /dev/loop* ; do losetup $f ; done

I don't think increasing max_loop will create any more /dev/loop*
devices if you run out - you'd need to mknod them.

>  
> As I said before I only get this error sometimes. If i repeat the xm 
> create command, it usually starts the domain the second time. The 
> problem with this is that I cant rely on the domains to get 
> automatically restarted after reboot.
>  
> Here is the complete output from xend-debug.log if that helps.
>  
> network start bridge=xen-br0 netdev=eth0 antispoof=no
> VIRTUAL MEMORY ARRANGEMENT:
>  Loaded kernel: c0100000->c038ad18
>  Init. ramdisk: c038b000->c038b000
>  Phys-Mach map: c038b000->c039b000
>  Page tables:   c039b000->c039e000
>  Start info:    c039e000->c039f000
>  Boot stack:    c039f000->c03a0000
>  TOTAL:         c0000000->c0800000
>  ENTRY ADDRESS: c0100000
> ioctl: LOOP_SET_FD: Device or resource busy
> op_create> Deferred Exception creating domain: [Errno 4] Interrupted 
> system call
> Traceback (most recent call last):
>   File "/usr/lib/python2.3/site-packages/twisted/internet/defer.py", 
> line 338, in _runCallbacks
>     self.result = callback(self.result, *args, **kw)
>   File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py", 
> line 958, in <lambda>
>     d.addCallback(lambda x: self.create_devices())
>   File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py", 
> line 785, in create_devices
>     v = dev_handler(self, dev, dev_index)
>   File "/usr/lib/python2.3/site-packages/xen/xend/XendDomainInfo.py", 
> line 1085, in vm_dev_vbd
>     defer = ctrl.attachDevice(idx, val, recreate=recreate)
>   File "/usr/lib/python2.3/site-packages/xen/xend/server/blkif.py", line 
> 495, in attachDevice
>     d = dev.attach()
>   File "/usr/lib/python2.3/site-packages/xen/xend/server/blkif.py", line 
> 314, in attach
>     node = Blkctl.block('bind', self.type, self.params)
>   File "/usr/lib/python2.3/site-packages/xen/xend/Blkctl.py", line 40, 
> in block
>     output = out.readline()
> IOError: [Errno 4] Interrupted system call
> Hopefully I am doing something dumb somewhere and there is a quick fix 
> so I can get on to setting up my project page :)
>  
> Thanks in advance
>  
> Tom

Thanks,

Mike




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Re: 'Interrupted system call' booting domains

[Keir Fraser]

> As I said before I only get this error sometimes. If i repeat the xm
> create command, it usually starts the domain the second time. The
> problem with this is that I cant rely on the domains to get
> automatically restarted after reboot. 
>
> Hopefully I am doing something dumb somewhere and there is a quick fix
> so I can get on to setting up my project page :)

Direct use of readline() is dangerous in xend. It looks like the bug
is fixed in 2.0-testing so you might want to give that repository a
try. I expect we will push current 2.0-testing into the main 2.0
respository quite soon now.

 -- Keir


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Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
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