From: Klemens Nanni <kn@openbsd.org>
Subject: ffmpeg: ILL_BTCFI in ff_vp9_idct_4x4_internal_avx2() via tdesktop
To: ports <ports@openbsd.org>
Cc: Brad Smith <brad@comstyle.com>, "Kirill A. Korinsky" <kirill@korins.ky>
Date: Fri, 12 Jun 2026 19:48:56 +0000

Yesterday I updated my packages and built new tdesktop,
now it crashes when opening chats;  no reproducer yet.

ffmpeg-8.1.1v1      audio/video converter and streamer
tdesktop-6.9.1      Telegram Desktop messenger

 81826 Telegram PSIG  SIGILL SIG_DFL code=ILL_BTCFI addr=0x397a1703911 trapno=21

Core was generated by `Telegram'.
Program terminated with signal SIGILL, Illegal instruction.
#0  0x00000397a1703911 in ff_vp9_idct_4x4_internal_avx2.pass2 () from /usr/local/lib/libavcodec.so.27.2
[Current thread is 1 (process 317345)]
#0  0x00000397a1703911 in ff_vp9_idct_4x4_internal_avx2.pass2 () from /usr/local/lib/libavcodec.so.27.2
#1  0x00000397a14c1cee in ff_vp9_intra_recon_8bpp () from /usr/local/lib/libavcodec.so.27.2
#2  0x00000397a1450b10 in ff_vp9_decode_block () from /usr/local/lib/libavcodec.so.27.2
#3  0x00000397a1447ac1 in decode_sb () from /usr/local/lib/libavcodec.so.27.2
#4  0x00000397a1447f39 in decode_sb () from /usr/local/lib/libavcodec.so.27.2
#5  0x00000397a1447e9b in decode_sb () from /usr/local/lib/libavcodec.so.27.2
#6  0x00000397a1447e9b in decode_sb () from /usr/local/lib/libavcodec.so.27.2
#7  0x00000397a1440d12 in vp9_decode_frame () from /usr/local/lib/libavcodec.so.27.2
#8  0x00000397a0defe41 in ff_decode_receive_frame_internal () from /usr/local/lib/libavcodec.so.27.2
#9  0x00000397a0df0573 in decode_receive_frame_internal () from /usr/local/lib/libavcodec.so.27.2
#10 0x00000397a0df04f2 in avcodec_send_packet () from /usr/local/lib/libavcodec.so.27.2
#11 0x000003973e8583eb in try_decode_frame () from /usr/local/lib/libavformat.so.24.2
#12 0x000003973e856477 in avformat_find_stream_info () from /usr/local/lib/libavformat.so.24.2
#13 0x00000394c50e89f6 in ?? ()
#14 0x00000394c50ea4e7 in ?? ()
#15 0x00000394c763a009 in ?? ()
#16 0x00000394cba638f1 in ?? ()
#17 0x00000396e40ba5d5 in _dispatch_worker_thread () from /usr/local/lib/libdispatch.so.0.0
#18 0x0000039707398c92 in _rthread_start (v=0x397a0b431e0 <pw_m8423x2>) at /usr/src/lib/librthread/rthread.c:99
#19 0x00000396e8237eca in __tfork_thread () at /usr/src/lib/libc/arch/amd64/sys/tfork_thread.S:87

cpu0 at mainbus0: apid 0 (boot processor)
cpu0: 12th Gen Intel(R) Core(TM) i7-1270P, 2095.31 MHz, 06-9a-03, patch 0000043b
cpu0: cpuid 1 edx=bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> ecx=77fafbff<SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND>
cpu0: cpuid 6 eax=df8ff7<SENSOR,ARAT,PTS> ecx=409<EFFFREQ>
cpu0: cpuid 7.0 ebx=239c27eb<FSGSBASE,TSC_ADJUST,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,RDSEED,ADX,SMAP,CLFLUSHOPT,CLWB,PT,SHA> ecx=98c027ac<UMIP,PKU,WAITPKG,PKS> edx=fc1cc410<MD_CLEAR,IBT,IBRS,IBPB,STIBP,L1DF,SSBD>