[FFmpeg-trac] #5231(avcodec:new): Crashes in ff_deblock_v_luma_8_sse2

FFmpeg trac at avcodec.org
Fri Feb 12 18:27:58 CET 2016

#5231: Crashes in ff_deblock_v_luma_8_sse2
             Reporter:  mi           |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  avcodec
              Version:  unspecified  |               Resolution:
             Keywords:  h264 crash   |               Blocked By:
  SIGSEGV                            |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |

Comment (by mi):

 Replying to [comment:4 cehoyos]:
 > The stack trace looks broken, could you test with {{{--disable-
 optimizations}}} and/or {{{--enable-debug=3}}}?

 Simply adding those two flags breaks build -- various *_sse4 and _ssse3
 symbols remain "not found" at link-time. I had to ''also'' add `--disable-
 sse4` and `--disable-ssse3` to configure-arguments to get things to build.
 The crash is still here, I'll attach the output of gdb-session.

 > Unless you find the place where memory with insufficient alignment is
 allocated: I hope this isn't just a compiler bug...

 Searching Internet for the name of the function brings up plenty of hits
 -- with work-arounds offered for gcc, but not for clang. BTW, you added
 "SIGSEGV" as the keyword to this bug -- it is `SIGBUS` I'm seeing, not
 segmentation fault.

 Replying to [comment:5 cehoyos]:
 > Which is not ok, see the first paragraph on

 Your having codified it does not make it fair. You could've demanded,
 every bug-submitter first reproduce their problem on SCO Unix, for
 example. Or see, if it is still there if they shake a dead chicken, while
 running your code. A good way to keep the bug-database nice and clean, is
 not it?

 Reporting a problem in the latest ''release'' should be sufficient. If you
 have not seen fit to release, what is currently at the top of your master-
 branch, making users struggle with it -- in addition to struggling with
 the bug itself and the gdb -- is not fair.

Ticket URL: <https://trac.ffmpeg.org/ticket/5231#comment:6>
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