Re: pdb missing files?

["Jonathan M. McCune" <jonmccune@cmu.edu>]

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Hi Kip,

gdbserver-xen is behaving as I expect, now that I've turned off 
crash_debug in Rules.mk.  Thanks again for your helpful suggestions.  
Indeed, I am interested in debugging domU.  However, the domU kernel 
I've built is crashing and / or xend is crashing before the domain can 
even be started "paused".

I can boot an unmodified domU (except for turning on the appropriate 
debug options) and debug as expected.  However, the kernel I am 
interested in debugging is causing xend to crash, which apparently 
results in errors from xm.  Upon a restart of xend, `xm list` doesn't 
show any new domains.  Other utilities do, though, more on this in a sec...

xm complains about http errors when I try to create a domU with my debug 
kernel from the dom0 console.  When xm complains like this, xend 
crashes.  When I restart xend, `xm list` does not show the new domain.  
However, `xm top` does show that domain, the memory it uses, and its 
status is "paused".  Further, if I use the Ctrl+A Ctrl+A Ctrl+A Xen 
console via serial cable, and select option 'q' (dump task queues + 
guest state), the new domain appears.

If I try to use gdbserver-xen to connect to one of my 
invisible-to-xm-list domains, gdbserver-xen segfaults once gdb connects 
to it.  I believe this is interesting because gdbserver-xen will 
complain about nonexistant domains if I pass it a domain id which has 
never been used this boot cycle.  If I pass it a domain which ran 
successfully, but has shutdown, it says "getdomaininfo failed".  Hence, 
I believe the segfault of gdbserver-xen is directly related to the 
changes I've made to the kernel I want to debug.

I'm not sure if this a bug in xm or xend, or if it is an artifact of a 
bad modification that I've made to the kernel I'm trying to debug. 

I have included the output from `xm` and the output from 'q':

Any ideas?

Thanks,
-Jon


root:11:56 AM:xen_conf $ xm create -p ttylinux.xm
Using config file "ttylinux.xm".
Unexpected error: httplib.BadStatusLine

Please report to xen-devel@lists.xensource.com
Traceback (most recent call last):
  File "/usr/sbin/xm", line 10, in ?
    main.main(sys.argv)
  File "/usr/lib/python/xen/xm/main.py", line 683, in main
    rc = cmd(args)
  File "<string>", line 1, in <lambda>
  File "/usr/lib/python/xen/xm/main.py", line 304, in xm_subcommand
    cmd.main(["bogus"] + args)
  File "/usr/lib/python/xen/xm/create.py", line 838, in main
    dom = make_domain(opts, config)
  File "/usr/lib/python/xen/xm/create.py", line 738, in make_domain
    dominfo = server.xend_domain_create(config)
  File "/usr/lib/python/xen/xend/XendClient.py", line 201, in 
xend_domain_create
    {'op'      : 'create',
  File "/usr/lib/python/xen/xend/XendClient.py", line 153, in xendPost
    return self.client.xendPost(url, data)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 101, in xendPost
    return self.xendRequest(url, "POST", args)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 172, in xendRequest
    resp = conn.getresponse()
  File "/usr/lib/python2.3/httplib.py", line 781, in getresponse
    response.begin()
  File "/usr/lib/python2.3/httplib.py", line 273, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.3/httplib.py", line 237, in _read_status
    raise BadStatusLine(line)
httplib.BadStatusLine






(XEN) 'q' pressed -> dumping task queues (now=0x1DD:43C5E37C)
(XEN) Xen: DOM 0, flags=d refcnt=3 nr_pages=116912 xenheap_pages=5
(XEN) XenPage 001c8000: caf=80000002, taf=f0000002
(XEN) XenPage 001c9000: caf=80000002, taf=f0000002
(XEN) XenPage 001ca000: caf=80000002, taf=f0000002
(XEN) XenPage 001cb000: caf=80000002, taf=f0000002
(XEN) XenPage 001df000: caf=80000002, taf=f0000002
(XEN) Shared_info@001df000: caf=80000002, taf=f0000002
(XEN) Guest: ff1c6080 CPU 0 [has=F] flags=3 upcall_pend = 01, 
upcall_mask = 00
(XEN) Notifying guest... 0/0
(XEN) port 1/4 stat 0 0 -1
(XEN) Xen: DOM 1, flags=0 refcnt=3 nr_pages=2560 xenheap_pages=5
(XEN) XenPage 001d0000: caf=80000001, taf=f0000001
(XEN) XenPage 001d1000: caf=80000001, taf=f0000001
(XEN) XenPage 001d2000: caf=80000001, taf=f0000001
(XEN) XenPage 001d3000: caf=80000001, taf=f0000001
(XEN) XenPage 001d4000: caf=80000001, taf=f0000001
(XEN) Shared_info@001d4000: caf=80000001, taf=f0000001
(XEN) Guest: ff1d6080 CPU 0 [has=F] flags=10 upcall_pend = 00, 
upcall_mask = 00
(XEN) Notifying guest... 1/0
(XEN) port 1/0 stat 0 0 0




Kip Macy wrote:

>What PDB brings to the table is the ability to debug several domains at once
>(think clustering). For his needs gdbserver-xen will likely suffice.
>
>-Kip
>
>
>
>  
>
>>Yes, certainly it is.
>>
>>PDB relies on xcs to pass message control, but since when xcs has been
>>removed, nobody updates PDB to catch up the change.
>>
>>PDB should now exploit the xenstore interface.
>>
>>Hieu.
>>
>>_______________________________________________
>>Xen-devel mailing list
>>Xen-devel@lists.xensource.com
>>http://lists.xensource.com/xen-devel
>>
>>    
>>

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