[vlc-devel] Core input code race condition

[Rémi Denis-Courmont]

Le mercredi 4 mars 2009 09:14:25 xxcv, vous avez écrit :
> #0  0x6a55bee6 in decoder_SynchroNewPicture (p_synchro=0x0,
> i_coding_type=2,
>     i_repeat_field=2, next_pts=877466, next_dts=777366, b_low_delay=false)
>     at input/decoder_synchro.c:404
> #1  0x66741b77 in DecodeBlock (p_dec=0x1f350968, pp_block=0x13f0fe54)
>     at libmpeg2.c:420
> #2  0x6a55a760 in DecoderDecodeVideo (p_dec=0x1f350968,
>     p_block=<incomplete type>) at input/decoder.c:1350
> #3  0x6a559de2 in DecoderProcess (p_dec=0x1f350968, p_block=<incomplete
> type>)
>     at input/decoder.c:1818
> #4  0x6a55a1b7 in DecoderThread (p_this=0x1f350968) at input/decoder.c:884
> #5  0x6a58aa2f in thread_entry (data=0x19cdae18) at misc/threads.c:960
> #6  0x6a58a717 in vlc_entry (data=0x1f2dd160) at misc/threads.c:647

Hmm. This is simply the mpeg2 decoder passing an invalid NULL pointer to the 
picture synchro helper. As there are no thread-safety considerations here, I 
would simply assume that you managed to fail the MPEG2 decoder state machine 
with some invalid input.

-- 
Rémi Denis-Courmont
http://git.remlab.net/cgi-bin/gitweb.cgi?p=vlc-courmisch.git;a=summary