Tobi pointed out that the crashing thread crashes when trying to
execute the first instruction in the page
VM_ALLOCATE
119af0000-
119af1000 [ 4K] r-x/rwx SM=PRV
which is dynamically allocated with VM_ALLOCATE (as opposed to being
a memory-mapped binary). Its protections (r-x/rwx) suggest that its
being used for JIT, so this code isn't signed, so the process
is killed by the hardened runtime.
We suspect FFmpeg is doing some JIT but perhaps only on x86_64
(as I couldn't reproduce the crash on arm64).
<true/>
<key>com.apple.security.cs.allow-dyld-environment-variables</key>
<true/>
+ <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
+ <true/>
</dict>
</plist>
EOF