This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


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

To: "Ryan Harper" <ryanh@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] gdbserver-xen x86_64 paravirt guest debugging
From: "Kamble, Nitin A" <nitin.a.kamble@xxxxxxxxx>
Date: Wed, 19 Apr 2006 15:16:01 -0700
Delivery-date: Wed, 19 Apr 2006 15:16:32 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcZj/hVLtd8qy3NrT8OLv25Ob0VJRwAAI68Q
Thread-topic: [Xen-devel] gdbserver-xen x86_64 paravirt guest debugging
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,
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
>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
>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:
>linux-x86_64-xen/gdb/gdbserver/gdbserver-xen --attach 1
>domain currently paused
>Attached; pid = 1
>Listening on port 9999
>Remote debugging from host
>Program received signal SIGSEGV, Segmentation fault.
>0x00002b2611bf410a in map_domain_va_64 (xc_handle=7, cpu=0,
>    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
>Xen-devel mailing list

Xen-devel mailing list