[vlc-devel] [vlc-commits] Use str_format_meta for snapshots

[Rémi Denis-Courmont]

On Fri, 17 Jan 2014 08:25:44 +0100, Rafaël Carré <funman at videolan.org>
wrote:
> On 01/17/14 03:15, Rémi Denis-Courmont wrote:
>> On Thu, 16 Jan 2014 22:01:12 +0100 (CET), git at videolan.org (Rafaël
>> Carré)
>> wrote:
>>> vlc | branch: master | Rafaël Carré <funman at videolan.org> | Thu Jan 16
>>> 22:00:52 2014 +0100| [17818d7bce710b281bc9d012aaf84a18b59924e2] |
>>> committer: Rafaël Carré
>>>
>>> Use str_format_meta for snapshots
>> 
>> The vout outlives the subsequent inputs, so this is obviously invalid.
>> The
>> pointer is potentially dangling there.
> 
> The vout indeed survives subsequent inputs but its configuration is
> updated (see vout_Request) so vout->p->input should stay valid.

Of course not. First that does not solve the synchronization of memory
access to the pointer. Second, there is intrinsically a window of time when
the input is invalid; since there is a window of time when there is no
input at all. (And last, the current code with pointer comparison is even
flaky, since the "new" input could have the same address as the "old"
input, and yet they would be different input instances; but at least that
is not a race unlike your patch.)

> Sorry but I am not convinced this should be removed, as far as I can
> tell the vout references the input properly.

It looks more like you are (again) defending a ridiculous side of an
argument for the sake of having an argument.

-- 
Rémi Denis-Courmont
Sent from my collocated server