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Re: [Qemu-devel] [PATCH 0/3] scripts/qemu-gdb: Add event tracing support
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH 0/3] scripts/qemu-gdb: Add event tracing support |
Date: |
Fri, 15 May 2015 15:36:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2015-05-15 15:21, Markus Armbruster wrote:
> Jan Kiszka <address@hidden> writes:
>
>> On 2015-05-15 14:18, Markus Armbruster wrote:
>>> Peter Maydell <address@hidden> writes:
>>>
>>>> On 15 May 2015 at 08:58, Markus Armbruster <address@hidden> wrote:
>>>>> Since you're touching qemu-gdb.py anyway, could you stick in a brief
>>>>> comment explaining how to put it to use?
>>>>
>>>> Good idea. It turns out the answer is just "source it from gdb",
>>>> but it took me a little while to find that out, so worth commenting.
>>>> I also have a patch which makes it do the 'ignore SIGUSR1' bit
>>>> by doing 'handle SIGUSR1 pass noprint nostop' for you.
>>>
>>> Here's how to load scripts/qemu-gdb.py automatically:
>>>
>>> * Apply the appended patch to turn it into a gdb init file
>>>
>>> That's what it is, after all. It's not a standalone Python program.
>>>
>>> * Tell gdb to trust it
>>>
>>> Add a line like
>>>
>>> add-auto-load-safe-path ~/work/qemu/scripts/qemu-gdb.py
>>>
>>> to your ~/.gdbinit
>>>
>>> * Link it into the directory where you run gdb --args qemu...
>>>
>>> * Verify it works:
>>>
>>> $ gdb
>>> [...]
>>> (gdb) help qemu
>>> Prefix for QEMU debug support commands
>>>
>>> List of qemu subcommands:
>>>
>>> qemu coroutine -- Display coroutine backtrace
>>> qemu mtree -- Display the memory tree hierarchy
>>>
>>> Type "help qemu" followed by qemu subcommand name for full
>>> documentation.
>>> Type "apropos word" to search for commands related to "word".
>>> Command name abbreviations are allowed if unambiguous.
>>> (gdb)
>>>
>>> If you know a better way to do this, please post it.
>>>
>>
>> Yep, that's the basic idea behind gdb python scripts: myapp-gdb.py gets
>> auto-pulled on "gdb myapp". Since some gdb 7.x, we have that security
>> feature above which prevents pulling from arbitrary sources.
>>
>>>
>>> diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py
>>> index 6c7f4fb..ac3087c 100644
>>> --- a/scripts/qemu-gdb.py
>>> +++ b/scripts/qemu-gdb.py
>>> @@ -1,5 +1,3 @@
>>> -#!/usr/bin/python
>>> -
>>> # GDB debugging support
>>> #
>>> # Copyright 2012 Red Hat, Inc. and/or its affiliates
>>> @@ -13,7 +11,7 @@
>>> # Contributions after 2012-01-13 are licensed under the terms of the
>>> # GNU GPL, version 2 or (at your option) any later version.
>>>
>>> -
>>> +python
>>
>> What is this line doing?
>
> Found here:
> https://stackoverflow.com/questions/16553283/python-code-in-gdb-init-file-gdbinit
The author there puts his code into .gdbinit, which is a gdb script, not
a python one.
>
> It doesn't work for me without it.
When sourcing? Works fine here (gdb 7.7.something).
In any case, when you pull in the script via auto-load, that extra
non-python statement will break. Try "python python". ;)
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
Re: [Qemu-devel] [PATCH 0/3] scripts/qemu-gdb: Add event tracing support, Stefan Hajnoczi, 2015/05/18
Re: [Qemu-devel] [PATCH 0/3] scripts/qemu-gdb: Add event tracing support, Stefan Hajnoczi, 2015/05/18