RE: [Xen-devel] gdbserver-xen x86_64 paravirt guest debugging

["Kamble, Nitin A" <nitin.a.kamble@xxxxxxxxx>]

Hi Ryan,
  I am writing a paper for debugging Linux kernel using the Xen and the
gdbserver. So with that you will get more details.

  For the quick solution for your problem, you need to run "set
architecture i386:x86-64:intel" command in the gdb before attaching.

Thanks & Regards,
Nitin
------------------------------------------------------------------------
-----------
Open Source Technology Center, Intel Corp

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
>bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Ryan Harper
>Sent: Wednesday, April 19, 2006 3:10 PM
>To: xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: [Xen-devel] gdbserver-xen x86_64 paravirt guest debugging
>
>I've attempted to debug live x86_64 domU domains with little success.
>gdbserver-xen segfaults and I've starting running gdb on gdbserver-xen
>to see where things are going south.
>
>I kick off the server under gdb, and then run gdb client and remote
>attach.  This appears to succeed, and gives me:
>
>[New Thread 0]
>[Switching to Thread 0]
>0xffffffff8014e258 in softlockup_tick (regs=0xffff880026c6fcd8) at
>kernel/softlockup.c:50
>50              unsigned long timestamp = per_cpu(timestamp, this_cpu);
>
>But when I ask for a backtrace:
>
>(gdb) bt
>#0  0xffffffff8014e258 in softlockup_tick (regs=0xffff880026c6fcd8) at
>kernel/softlockup.c:50
>Ignoring packet error, continuing...
>Reply contains invalid hex digit 116
>
>
>On the other side (gdbserver-xen) I see:
>
>(gdb) run
>The program being debugged has been started already.
>Start it from the beginning? (y or n) y
>
>Starting program:
>/home/rharper/work/openhype/xen/unstable/hg/d/tools/debugger/gdb/gdb-6.
2.1-
>linux-x86_64-xen/gdb/gdbserver/gdbserver-xen 127.0.0.1:9999 --attach 1
>domain currently paused
>Attached; pid = 1
>Listening on port 9999
>Remote debugging from host 127.0.0.1
>
>Program received signal SIGSEGV, Segmentation fault.
>0x00002b2611bf410a in map_domain_va_64 (xc_handle=7, cpu=0,
>guest_va=0xffffffff80364ed0,
>    perm=1) at xc_ptrace.c:295
>295         l3p = page_array[l3p];
>
>Some inspection:
>
>(gdb) p l3p
>$4 = 796261
>(gdb) p nr_pages
>$5 = 196608
>
>page_array only has 196k entries AFAICT, so this seems problematic.
>
>Anyone have x86_64 paravirt guest debugging working on latest unstable?
>
>--
>Ryan Harper
>Software Engineer; Linux Technology Center
>IBM Corp., Austin, Tx
>(512) 838-9253   T/L: 678-9253
>ryanh@xxxxxxxxxx
>
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@xxxxxxxxxxxxxxxxxxx
>http://lists.xensource.com/xen-devel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel