I observed the following crash:
Code Type: ARM-64 (Native)
Parent Process: launchd [1]
User ID: 0
Date/Time: 2025-10-07 13:48:29.082
OS Version: macOS 15.6 (24G84)
Report Version: 12
Anonymous UUID: 8B651788-4B2E-7869-516B-1DA0D60F3744
Crashed Thread: 3 Dispatch queue: NEFlow queue
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000054
...
Thread 3 Crashed: Dispatch queue: NEFlow queue
0 libdispatch.dylib 0x000000019af6da34 dispatch_async + 192
1 libnetworkextension.dylib 0x00000001b0cf8580 __flow_startup_block_invoke.216 + 124
2 com.apple.NetworkExtension 0x00000001adf97da8 __88-[NEExtensionAppProxyProviderContext setInitialFlowDivertControlSocket:extraValidation:]_block_invoke.90 + 860
3 libnetworkextension.dylib 0x00000001b0cf8140 __flow_startup_block_invoke.214 + 172
4 libdispatch.dylib 0x000000019af67b2c _dispatch_call_block_and_release + 32
5 libdispatch.dylib 0x000000019af8185c _dispatch_client_callout + 16
6 libdispatch.dylib 0x000000019af70350 _dispatch_lane_serial_drain + 740
7 libdispatch.dylib 0x000000019af70e2c _dispatch_lane_invoke + 388
8 libdispatch.dylib 0x000000019af7b264 _dispatch_root_queue_drain_deferred_wlh + 292
9 libdispatch.dylib 0x000000019af7aae8 _dispatch_workloop_worker_thread + 540
10 libsystem_pthread.dylib 0x000000019b11be64 _pthread_wqthread + 292
11 libsystem_pthread.dylib 0x000000019b11ab74 start_wqthread + 8
...
It appears that the crash is caused by the flow director queue becoming NULL when dispatch_async is called (accessing address 0x0000000000000054). Meanwhile, my transparent proxy was still running.
I'm wondering if this is a known issue or if anyone else has encountered the same problem. @eskimo