[Ffmpeg-devel] FFMpeg crash on decoding H.264 incomplete frame.

[Alexander Chemeris]

Hello,

On 12/4/06, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Mon, Dec 04, 2006 at 04:16:35PM +0300, Alexander Chemeris wrote:
> > On 12/2/06, Michael Niedermayer <michaelni at gmx.at> wrote:
> > >On Wed, Nov 29, 2006 at 04:12:55PM +0300, Alexander Chemeris wrote:
> > >> (gdb) run
> > >> Starting program: C:\Program Files\FFmpeg/ffmpeg.exe -f h264 -i
> > >crash.h264
> > >debugging should always use ffmpeg_g!
>                                ^^^^^^^^
Do not make big difference here, since I use debug version of *library* and
error located in library, not in the ffmpeg program.

Here is debug output with ffmpeg_g:

GNU gdb 5.2.1
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This GDB was configured as "i686-pc-mingw32"...
(gdb) run
Starting program: C:\Program Files\FFmpeg/ffmpeg_g.exe -f h264 -i 1.h264

Program received signal SIGSEGV, Segmentation fault.
0x1016be32 in decode_residual (h=0x0, gb=0x22ee30, block=0x6aaac0, n=0,
    scantable=0x100218c0 "UWVS\203?\b\213D$$\213|$\034\213t$
\203?\003\213?\207?\032", qmul=0x10021990, max_coeff=268573232) at
bitstream.h:882
	in bitstream.h
882	bitstream.h: No such file or directory.
(gdb) bt
#0  0x1016be32 in decode_residual (h=0x0, gb=0x22ee30, block=0x6aaac0, n=0,
    scantable=0x100218c0 "UWVS\203?\b\213D$$\213|$\034\213t$
\203?\003\213?\207?\032", qmul=0x10021990, max_coeff=268573232) at
bitstream.h:882
#1  0x0022eec8 in ?? ()
#2  0x0064dbfc in ?? ()
#3  0x00403142 in output_packet (ist=) at ffmpeg.c:871
Cannot access memory at address 0xf008280
Cannot access memory at address 0xf008188
(gdb) disass $pc-32 $pc+32
Dump of assembler code from 0x1016be12 to 0x1016be52:
0x1016be12 <decode_residual+82>:	lea    (%ebx,%edi,1),%eax
0x1016be15 <decode_residual+85>:	cmp    $0x3f,%eax
0x1016be18 <decode_residual+88>:	jle    0x1016c0c8 <decode_residual+776>
0x1016be1e <decode_residual+94>:	and    $0x1f,%eax
0x1016be21 <decode_residual+97>:	mov    0x0(%ebp),%esi
0x1016be24 <decode_residual+100>:	mov    0x102ad7c0(,%eax,4),%ebx
0x1016be2b <decode_residual+107>:	mov    %esi,0x44(%esp,1)
0x1016be2f <decode_residual+111>:	shl    $0x4,%ebx
0x1016be32 <decode_residual+114>:	mov    0x10360fa4(%ebx),%edx
0x1016be38 <decode_residual+120>:	mov    0x8(%ebp),%ebx
0x1016be3b <decode_residual+123>:	mov    %ebx,%edi
0x1016be3d <decode_residual+125>:	mov    %ebx,%ecx
0x1016be3f <decode_residual+127>:	sar    $0x3,%edi
0x1016be42 <decode_residual+130>:	and    $0x7,%ecx
0x1016be45 <decode_residual+133>:	mov    (%esi,%edi,1),%eax
0x1016be48 <decode_residual+136>:	bswap  %eax
0x1016be4a <decode_residual+138>:	shl    %cl,%eax
0x1016be4c <decode_residual+140>:	shr    $0xf8,%eax
0x1016be4f <decode_residual+143>:	movswl 0x2(%edx,%eax,4),%esi
End of assembler dump.
(gdb) info all-registers
eax            0x1e	30
ecx            0x64dc90	6610064
edx            0x64fd88	6618504
ebx            0x6656f630	1716975152
esp            0x22ee30	0x22ee30
ebp            0x64fd88	0x64fd88
esi            0x64cb07	6605575
edi            0xff	255
eip            0x1016be32	0x1016be32
eflags         0x10206	66054
cs             0x1b	27
ss             0x23	35
ds             0x23	35
es             0x23	35
fs             0x3b	59
gs             0x0	0
st0            0	(raw 0x00000000000000000000)
st1            0	(raw 0x00000000000000000000)
st2            0	(raw 0x00000000000000000000)
st3            0	(raw 0x00000000000000000000)
st4            0	(raw 0x00000000000000000000)
st5            1	(raw 0x3fff8000000000000000)
st6            1	(raw 0x3fff8000000000000000)
st7            1	(raw 0x3fff8000000000000000)
fctrl          0xffff037f	-64641
fstat          0xffff4020	-49120
ftag           0xffffffff	-1
fiseg          0x1b	27
fioff          0x1011c647	269600327
foseg          0xffff0023	-65501
fooff          0x22f268	2290280
fop            0x1c9	457

-- 
Regards,
Alexander Chemeris.