[FFmpeg-trac] #272(avcodec:open): altivec specific code segfaults on ppc when compiled with --enable-pic

FFmpeg trac at avcodec.org
Thu Jun 9 19:20:50 CEST 2011

#272: altivec specific code segfaults on ppc when compiled with --enable-pic
Reporter:  kim         |       Owner:
    Type:  defect      |      Status:  open
Priority:  normal      |   Component:  avcodec
 Version:  git-master  |  Resolution:
Keywords:  ppc, PIC    |  Blocked By:
Blocking:              |  Reproduced:  0
Analyzed:  0           |

Comment (by kim):

 I have confirmed this with a stream from my internet/tv box. The sample is
 available here:


 (few seconds of a french commercial). Video is H264, Audio is AAC. When
 compiled with --enable-pic
 with commit a46b84d1204 reverted, ffplay plays audio and video fine. With
 plain master
 (f9ecb849ef3) it segfaults as explained above. The stream also plays fine
 on x86 vlc (just to check that it's not too corrupt).

 Here are more infos and I'm attaching a gdb trace with full disassembly of
 the function (instead of pc-32, pc+32).

 Machine is a G4 MacMini :

 processor       : 0
 cpu             : 7447A, altivec supported
 clock           : 1416.666661MHz
 revision        : 1.2 (pvr 8003 0102)
 bogomips        : 83.24
 timebase        : 41620997
 platform        : PowerMac
 model           : PowerMac10,1
 machine         : PowerMac10,1
 motherboard     : PowerMac10,1 MacRISC3 Power Macintosh
 detected as     : 287 (Mac mini)
 pmac flags      : 00000010
 L2 cache        : 512K unified
 pmac-generation : NewWorld
 Memory          : 1024 MB
 gcc version:

 Using built-in specs.
 Target: powerpc-linux-gnu
 Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
 4.5.2-8ubuntu4' --with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs
 --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-
 suffix=-4.5 --enable-shared --enable-multiarch --with-multiarch-defaults
 =powerpc-linux-gnu --enable-linker-build-id --with-system-zlib
 --libexecdir=/usr/lib/powerpc-linux-gnu --without-included-gettext
 --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.5
 --libdir=/usr/lib/powerpc-linux-gnu --enable-nls --with-sysroot=/
 --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
 --enable-plugin --enable-gold --enable-ld=default --with-plugin-ld=ld.gold
 --enable-objc-gc --enable-secureplt --disable-softfloat --enable-targets
 =powerpc-linux,powerpc64-linux --with-cpu=default32 --disable-werror
 --with-long-double-128 --enable-checking=release --build=powerpc-linux-gnu
 --host=powerpc-linux-gnu --target=powerpc-linux-gnu
 Thread model: posix
 gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)

 as version:

 GNU assembler version 2.21.0 (powerpc-linux-gnu) using BFD version (GNU
 Binutils for Ubuntu)

 distrib is ubuntu natty, ppc (libc6 version is 2.13 egcs)

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/272#comment:4>
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