This is trivial fix of hdacc_detach to avoid duplicated free on snd_hda
unloading.
The first try of detaching (kldunload) may results into "device busy" error,
but codec->fgs is freed by detach. Second try attempts to free codec->fgs again
and system panicks.
Here is example:
pcm0: unregister: channel pcm0:virtual:dsp0.vp0 busy (pid 3428) pulseaudio[3428] [oss] module-oss.c: DSP shutdown. pcm0: detached hdaa0: detached panic: Duplicate free of 0xfffff80412ee7d20 from zone 0xfffffe006bc0ba00 (malloc-32) slab 0xfffff80412ee7fc8(105) cpuid = 6 time = 1712999565 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0202f859e0 vpanic() at vpanic+0x135/frame 0xfffffe0202f85b10 panic() at panic+0x43/frame 0xfffffe0202f85b70 uma_dbg_free() at uma_dbg_free+0x105/frame 0xfffffe0202f85b90 uma_zfree_arg() at uma_zfree_arg+0x95/frame 0xfffffe0202f85be0 free() at free+0xa1/frame 0xfffffe0202f85c20 hdacc_detach() at hdacc_detach+0x2f/frame 0xfffffe0202f85c40 device_detach() at device_detach+0x197/frame 0xfffffe0202f85c80 devclass_driver_deleted() at devclass_driver_deleted+0x66/frame 0xfffffe0202f85c devclass_delete_driver() at devclass_delete_driver+0x81/frame 0xfffffe0202f85d00 driver_module_handler() at driver_module_handler+0xff/frame 0xfffffe0202f85d50 module_unload() at module_unload+0x32/frame 0xfffffe0202f85d70 linker_file_unload() at linker_file_unload+0x1eb/frame 0xfffffe0202f85db0 kern_kldunload() at kern_kldunload+0x18e/frame 0xfffffe0202f85e00 amd64_syscall() at amd64_syscall+0x153/frame 0xfffffe0202f85f30 fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0202f85f30
Tested on: Lenovo Thinkbook 16 G6+
MFC after: 3 days