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Re: [Qemu-devel] [PATCH 3/4] QError: Don't abort on multiple faults
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH 3/4] QError: Don't abort on multiple faults |
Date: |
Fri, 05 Feb 2010 15:21:13 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) |
Markus Armbruster <address@hidden> writes:
> Luiz Capitulino <address@hidden> writes:
>
>> Ideally, Monitor code should report an error only once and
>> return the error information up the call chain.
>>
>> To assure that this happens as expected and that no error is
>> lost, we have an assert() in qemu_error_internal().
>>
>> However, we still have not fully converted handlers using
>> monitor_printf() to report errors. As there can be multiple
>> monitor_printf() calls on an error, the assertion is easily
>> triggered when debugging is enabled; and we will get a memory
>> leak if it's not.
>>
>> The solution to this problem is to allow multiple faults by only
>> reporting the first one, and to release the additional error objects.
>
> I want this badly.
>
> [...]
Let me elaborate a bit. While this patch is a much wanted improvement,
what I *really* want is something else.
Right now, we have 41 uses of qemu_error_new(). We still have >300 uses
of monitor_printf(), many of them errors. Plus some 100 uses of
qemu_error(), which boils down to monitor_printf() when running within a
monitor. Not to mention >1000 uses of stderr.
To convert a monitor handler to QError, we have to make it report
exactly one error on every unsuccessful path, with qemu_error_new().
That's not too hard. Then we have to ensure it does not call
monitor_printf() directly (not hard either) or indirectly (ouch). I say
"ouch", because those prints can hide behind long call chains, in code
shared with other users. Cleaning up all those stray prints will take
time.
Without this patch, a stray print is fatal, unless it happens to be the
only one *and* there is no real error.
With this patch, we survive, but the UndefinedError triggered by the
stray print displaces any later real error.
What I really want is that stray prints do not mess with my real errors.
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, (continued)
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Luiz Capitulino, 2010/02/05
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Anthony Liguori, 2010/02/05
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Markus Armbruster, 2010/02/05
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Luiz Capitulino, 2010/02/08
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Anthony Liguori, 2010/02/08
- Re: [Qemu-devel] [PATCH 1/4] qjson: Improve debugging, Luiz Capitulino, 2010/02/08
[Qemu-devel] [PATCH 4/4] QMP: Don't leak on connection close, Luiz Capitulino, 2010/02/04
[Qemu-devel] [PATCH 2/4] Monitor: remove unneeded checks, Luiz Capitulino, 2010/02/04
[Qemu-devel] [PATCH 3/4] QError: Don't abort on multiple faults, Luiz Capitulino, 2010/02/04