RE: [Xen-devel] failed in debugging Xen hypervisor with gdb stub of xen

[Caz Yokoyama <cazyokoyama@xxxxxxxxx>]

Hello Kyle,

Do you have to use xen-3.2.0? Are you able to use xen-unstable? A couple of weeks ago, xen-unstable is able to accept break point, step and continue command. If you can use xen-unstable, I can guide you to set up for debugging Xen include those commands.

-caz

 

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From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of kyle.ma83
Sent: Saturday, August 29, 2009 11:36 PM
To: xen-devel
Subject: [Xen-devel] failed in debugging Xen hypervisor with gdb stub of xen

 

Hi,everyone

 

I recently want to debug Xen, and I just follow the xen-3.2/docs/misc/crashdb.txt. I use two machines (one linux host and one xen target)and can get the

 

xen booting message with serial to a remote linux host,I set debug=y in Config.mk and set crash_debug=y in xen/Rules.mk when make install xen and

 

arrange to pass gdb=com1 as a hypervisor command line argument, my grub is as followed:

 

title           xen-3.2.0

root            (hd0,0)

kernel          /boot/xen-3.2.0.gz hap com1=115200,8n1 console=com1,vga gdb=com1 sync_console

module          /boot/vmlinuz-2.6.18.8-xen root=/dev/sda1 ro xencons=ttyS0

module          /boot/initrd.img-2.6.18.8-xen

savedefault

 

I get the output infomation of Xen and Domain0, but the crashdb.txt says

 

give the escape character (^A by default) three times to talk to Xen (Xen prints `(XEN) *** Serial input -> Xen...'),  so I follow the instrucions. When I

 

press ctrl-A three times as soon as I see:

 

(XEN) **********************************************

(XEN) ******* WARNING: CONSOLE OUTPUT IS SYNCHRONOUS

(XEN) ******* This option is intended to aid debugging of Xen by ensuring

(XEN) ******* that all output is synchronously delivered on the serial line.

(XEN) ******* However it can introduce SIGNIFICANT latencies and affect

(XEN) ******* timekeeping. It is NOT recommended for production use!

(XEN) **********************************************

(XEN) 3... 2... 1... 

(XEN) Xen is relinquishing VGA console.

(XEN) *** Serial input -> DOM0 (type 'CTRL-a' three times to switch input to Xen)

(XEN) unpasue dom0

(XEN) Freed 92kB init memory.

 

but nothing happened, there is no infomation like "waiting for GDB attached...."  or something else,

 

 and at last get the "login as: " info , did I miss something or what should I do?

 

Could anyone give some more details and suggestions about it or how to debug Xen ?  I 'd appreciated it much.

 

Thanks a lot.

2009-08-30

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Kyle Ma

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