Re: [Qemu-devel] [PATCH] Python-lang gdb script to extract x86_64 guest vmcore from qemu coredump

[Laszlo Ersek <lersek@redhat.com>]

On 10/11/13 19:54, Stefan Hajnoczi wrote:
> On Thu, Sep 12, 2013 at 9:46 PM, Laszlo Ersek <lersek@redhat.com> wrote:
>> When qemu dies unexpectedly, for example in response to an explicit
>> abort() call, or (more importantly) when an external signal is delivered
>> to it that results in a coredump, sometimes it is useful to extract the
>> guest vmcore from the qemu process' memory image. The guest vmcore might
>> help understand an emulation problem in qemu, or help debug the guest.
>>
>> This script reimplements (and cuts many features of) the
>> qmp_dump_guest_memory() command in gdb/Python,
>>
>>   https://sourceware.org/gdb/current/onlinedocs/gdb/Python-API.html
>>
>> working off the saved memory image of the qemu process. The docstring in
>> the patch (serving as gdb help text) describes the limitations relative to
>> the QMP command.
>>
>> Dependencies of qmp_dump_guest_memory() have been reimplemented as needed.
>> I sought to follow the general structure, sticking to original function
>> names where possible. However, keeping it simple prevailed in some places.
>>
>> The patch has been tested with a 4 VCPU, 768 MB, RHEL-6.4
>> (2.6.32-358.el6.x86_64) guest:
> 
> I tried this out with qemu-kvm-1.1.2 and it worked after a few minor
> tweaks due to memory data structure changes.  I did hit a problem with
> crash since the vmlinux was 32-bit and the guest dump was 64-bit.  But
> from what I can tell dump-guest-memory works as advertised.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Could someone please pick up the patch?

Thanks!
Laszlo