Re: kvm guest debug using gdb on x86

[Jan Kiszka <jan.kiszka@siemens.com>]

Aneesh Kumar K.V wrote:
> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
>> Hi,
>>
>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
>> the guest debugging with gdb. I get the following error.
>>
>> $gdb ./vmlinux
>> GNU gdb 6.8-debian
>> Copyright (C) 2008 Free Software Foundation, Inc.
>> License GPLv3+: GNU GPL version 3 or later
>> <http://gnu.org/licenses/gpl.html>
>> This is free software: you are free to change and redistribute it.
>> There is NO WARRANTY, to the extent permitted by law.  Type "show
>> copying"
>> and "show warranty" for details.
>> This GDB was configured as "i486-linux-gnu"...
>> (gdb) b do_fork
>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
>> (gdb) target remote localhost:1234
>> Remote debugging using localhost:1234
>> [New Thread 1]
>> Remote 'g' packet reply is too long:
>> 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
 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> (gdb)
>>
>> any patches that i can try ?
> 
> Works better with the four patches found at
> 
> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
> 
> But a next and continue doesn't get the prompt back on gdb. The guest
> does stops the execution.

What arch is host and guest (x86-32 or -64)? What KVM versions are you
using? Are you sure that guest and vmlinux matches?

Jan

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