Re: [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals

["Andreas Färber" <afaerber@suse.de>]

Am 18.10.2012 12:43, schrieb Kevin Wolf:
> Am 17.10.2012 23:24, schrieb Tim Hardeck:
>> On Wednesday 17 October 2012 17:00:15 Andreas Färber wrote:
>>> Am 14.10.2012 15:08, schrieb Tim Hardeck:
>>>> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list
>>>> QEMU segfaults.
>>>
>>> Can this be reproduced by a user today? Or is this just fixing the case
>>> that a developer forgot to initialize a list?
>> I am not sure but in this case it happened during an early VNC connection 
>> state failure which most likely wouldn't happen to regular users.
>> I triggered it while working on the VNC connection part.
>>
>> The issue could most likely be also fixed in the VNC connection initialization 
>> process but if this changes doesn't have a relevant performance impact they 
>> might prevent some other/future crashes.
> 
> At the same time, it could be hiding real bugs, where ignoring the
> QLIST_REMOVE() isn't the right fix. I can see your point, but I would be
> careful with making interfaces less strict.

What I don't get is, why is avoiding a NULL pointer dereference any
better from accessing random memory through an uninitialized pointer? Or
am I getting "uninitialized" wrong?

> In any case, I don't think this qualifies for qemu-trivial, Andreas.

Maybe not, but we don't have a clear maintainer that I'm aware of, and
no one else reviewed it for several days before I did. ;)

Andreas

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