[FFmpeg-trac] #9060(swscale:new): libswscale crash with Neon - aarch64

[FFmpeg]

#9060: libswscale crash with Neon - aarch64
---------------------------------+--------------------------------------
             Reporter:  kuba456  |                     Type:  defect
               Status:  new      |                 Priority:  normal
            Component:  swscale  |                  Version:  git-master
             Keywords:           |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
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 Hi there, this is my first post so please bare with me :)
 I'm currently in the process of debugging a ffmpeg crash and I'm reaching
 out for some tips how to approach this. Reproducing the steps may be quite
 involved as the crash happens in the application which depends on ffmpeg
 library (libswscale). This is a custom build of Blender animation package
 (build on Aarch64) and the crash happens if ffmpeg is configured with Neon
 instructions. Here is the stack trace:


 {{{
 Thread 1 "blender" received signal SIGSEGV, Segmentation fault.
 0x000000000257e320 in ff_yuv420p_to_rgba_neon () at
 libswscale/aarch64/yuv2rgb_neon.S:211
 211     declare_rgb_funcs yuv420p
 (gdb) bt
 #0  0x000000000257e320 in ff_yuv420p_to_rgba_neon () at
 libswscale/aarch64/yuv2rgb_neon.S:211
 #1  0x000000000257cfe0 in yuv420p_to_rgba_neon_wrapper () at
 libswscale/aarch64/swscale_unscaled.c:61
 #2  0x000000000253361c in sws_scale () at libswscale/swscale.c:970
 #3  0x0000000000dabd44 in IMB_anim_absolute ()
 #4  0x0000000000b2384c in openanim ()
 #5  0x0000000000a59850 in BKE_sequencer_add_movie_strip ()
 #6  0x0000000000abd444 in sequencer_add_generic_strip_exec ()
 #7  0x0000000000a06c38 in wm_operator_invoke ()
 #8  0x0000000000a0a894 in wm_handlers_do_intern ()
 #9  0x0000000000a0abf0 in wm_handlers_do ()
 #10 0x0000000000a0b4b8 in wm_event_do_handlers ()
 #11 0x0000000000a02590 in WM_main ()
 #12 0x00000000009e27fc in main ()

 Linux nano 4.9.140-tegra 2020 aarch64

 }}}


 If I reconfigure ffmpeg and disable Neon all works great.
 I think my question at this point would be if anybody has seen similar
 issue in the past? Or could advise on the best way to narrow down the
 problem.

 Thank you,
 Kuba

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Ticket URL: <https://trac.ffmpeg.org/ticket/9060>
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