libplacebo and ffmpeg git tip segfault on init, core dumped

[Dennis E. Mungai]

Summary of the bug:

Any invocation of libplacebo now fails with an immediate segfault:

[23974.534317] vf#0:0[1003115]: segfault at 128 ip 000073c61c877e26 sp 000073c5c83e7508 error 4 in libavfilter.so.10.6.100[73c61c7ac000+315000] likely on CPU 14 (core 26, socket 0)
[23974.534337] Code: 41 5c c3 90 49 89 d4 eb d1 66 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 8b 87 28 01 00 00 c3 0f 1f 40 00 f3 0f 1e fa 31 c0 <48> 83 bf 28 01 00 00 00 0f 95 c0 c3 66 66 2e 0f 1f 84 00 00 00 00
[23978.918960] vf#0:0[1003155]: segfault at 128 ip 00007eec7bbbee26 sp 00007eec537e7508 error 4 in libavfilter.so.10.6.100[7eec7baf3000+315000] likely on CPU 12 (core 24, socket 0)
[23978.918978] Code: 41 5c c3 90 49 89 d4 eb d1 66 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 8b 87 28 01 00 00 c3 0f 1f 40 00 f3 0f 1e fa 31 c0 <48> 83 bf 28 01 00 00 00 0f 95 c0 c3 66 66 2e 0f 1f 84 00 00 00 00

Sample command:

In both instances, as tested on both NVIDIA and Intel Vulkan devices:

ffmpeg -init_hw_device "vulkan=vk:0,disable_multiplane=1" \
-f lavfi -i color=red:s=3840x2160 \
-vf hwupload,libplacebo,hwdownload,format=yuv420p -f null -

The pipeline(s) die with:

Input #0, lavfi, from 'color=red:s=3840x2160':
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0: Video: wrapped_avframe, yuv420p, 3840x2160 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 25 tbn
Stream mapping:
  Stream #0:0 -> #0:0 (wrapped_avframe (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
Segmentation fault (core dumped)

Suspected commit(s) 8160178dfc0e6bdaacf80dec58e595a9d595eedc

[Bill Li]

Reverting the suspected commit do fix the issue.

[Dennis E. Mungai]

Fixed by commit 3e9b0f7c018d8ada75b8af2b5ebeea75367dc0ca