[vlc-devel] [PATCH] glspectrum: destroy OpenGL vout from the thread that created it

[Felix Abecassis]

Here is the output of my run with gdb:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff321c700 (LWP 5565)]
0x00007fffba84c5a9 in glFinish () from /usr/lib/nvidia-319-updates/libGL.so.1
(gdb) disas
Dump of assembler code for function glFinish:
   0x00007fffba84c5a0 <+0>:     mov    %fs:0xffffffffffffff60,%rax
=> 0x00007fffba84c5a9 <+9>:     jmpq   *0x548(%rax)
   0x00007fffba84c5af <+15>:    int3
   0x00007fffba84c5b0 <+16>:    int3
   0x00007fffba84c5b1 <+17>:    int3
   0x00007fffba84c5b2 <+18>:    int3
   0x00007fffba84c5b3 <+19>:    int3
   0x00007fffba84c5b4 <+20>:    int3
   0x00007fffba84c5b5 <+21>:    int3
   0x00007fffba84c5b6 <+22>:    int3
   0x00007fffba84c5b7 <+23>:    int3
   0x00007fffba84c5b8 <+24>:    int3
   0x00007fffba84c5b9 <+25>:    int3
   0x00007fffba84c5ba <+26>:    int3
   0x00007fffba84c5bb <+27>:    int3
   0x00007fffba84c5bc <+28>:    int3
   0x00007fffba84c5bd <+29>:    int3
   0x00007fffba84c5be <+30>:    int3
   0x00007fffba84c5bf <+31>:    int3
End of assembler dump.
(gdb) print $rax
$1 = 0

If I'm not mistaken, the instruction "mov %fs:0xffffffffffffff60,%rax"
is the signature of thread-local storage usage. Thus we might actually
have a threading requirement, at least with this implementation of
OpenGL.

2014-03-06 13:59 GMT+01:00 Rémi Denis-Courmont <remi at remlab.net>:
> On Thu,  6 Mar 2014 12:41:51 +0100, Felix Abecassis
> <felix.abecassis at gmail.com> wrote:
>> Fix #9437
>
> This looks like a bug in the underlying video output, not the spectrum
> visualization. The caller is *only* responsible for serializing access to
> plugin callbacks; there are no (insane) requirements to invoke them from a
> unique thread.
>
> --
> Rémi Denis-Courmont
> Sent from my collocated server
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-- 
Félix Abecassis
http://felix.abecassis.me