[vlc-devel] [patch] ensure p_pic->pf_release calls are performed carefuly
thannoy at actech-innovation.com
Fri Apr 18 16:05:58 CEST 2008
Not sure I understand what you mean by "plugin", I will explain the
context more accurately. Also, since I have sent last mail I have
discovered that this problem is more weird as it appears to be.
Using git VLC and debian etch, I add a movie to the playlist with those
vlc -vvv --video-filter=deinterlace --deinterlace-mode=linear myFile.ts
I got a backtrace like this one
#0 0x00000000 in ?? ()
#1 0xaf59d550 in Deinterlace (p_filter=0x8457754, p_pic=0x83c5908) at
#2 0xb7f1d4ed in RunThread (p_vout=0x83c5374) at
#3 0xb7d79240 in start_thread ()
#4 0xb7e5149e in clone () from /lib/tls/i686/cmov/libc.so.6
Frame #1 is the unprotected call to pf_release().
NB: This command works fine:
vlc -vvv --vout-filter=deinterlace --deinterlace-mode=linear myFile.ts
The weird thing is on the frame 1, about deinterlace mode:
p_vout->p_sys->i_mode = 3
The mode 3 seems not to be the linear one:
#define DEINTERLACE_BLEND 3
#define DEINTERLACE_LINEAR 5
But maybe its normal since linear deinterlace seems disabled
p_filter->psz_object_name is ok: "deinterlace"
NB2: I can give you more infos such as full backtraces, or open a track
ticket if needed.
Le lundi 14 avril 2008 à 16:14 +0300, Rémi Denis-Courmont a écrit :
> Le mardi 8 avril 2008, Anthony Loiseau a écrit :
> > I have crossed a segmentation fault with a not protected call to
> > "p_pic->pf_release()" (video_filter/deinterlace.c:2185).
> > Most of those calls are already protected by "if( p_pic->pf_release
> > )", this patch ensure the test to be performed before all calls to
> > p_pic->pf_release().
> Do we know which plugins fail to set the callback? (and if it makes much
> sense not to set the callback except in some really corner cases).
> I suspect this is yet another attempt to use an object before it's been
> initialized. If that is the case, checking for pf_release NULL-ity will
> not fix the problem - merely hide it in some cases.
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