[vlc-devel] vlc bug/patch (Linux libvlccore): might hang in vlc_getProxyUrl() / waitpid()

[Marvin Scholz]

On 14 Dec 2016, at 21:33, Rémi Denis-Courmont wrote:

> Le tiistaina 13. joulukuuta 2016, 10.53.53 EET Andreas Luik a écrit :
>> Hello,
>>
>> bug report for vlc-2.1.6 (also in latest 2.2.4): we use libvlccore in 
>> one
>> thread of our multi-threaded application, and observe the function
>> vlc_getProxyUrl() to (often) hang forever in this loop:
>>
>> while (waitpid(pid, &(int){ 0 }, 0) == -1);
>>
>> The reason for this is that another thread might have already handled 
>> the
>> wait(), and the process "pid" does not exist anymore, resulting in
>> waitpid(pid) returning -1 (with errno==ECHILD) forever.
>
> This has already been discussed several years ago and the conclusion 
> was that
> this cannot be fixed in safe race-free manner in LibVLC. You need to 
> fix
> whatever brain-damaged code path is stealing PIDs from LibVLC.

Sorry but "brain-damaged" is really inappropriate tone IMHO.