On Sep 9, 2011, at 5:59 PM, Matthew Flatt wrote: > At Fri, 9 Sep 2011 17:39:38 -0700, John Clements wrote: >> It looks to me as though when a custodian-shutdown-all occurs, the >> custodian actions associated using scheme_add_managed() can be >> triggered while another thread is in the middle of a callback to an >> FFI-generated callback that includes the #:atomic declaration. Is >> this true? If true, is it only true for some certain set of >> (avoidable) circumstances? > > The possibility that comes to mind is a custodian shutdown triggered by > a memory-use limit. It looks easy and sensible to disallow that. > > Could that be what you saw, or should I look for other possibilities?
I believe it was a custodian-shutdown-all on a user thread triggered by clicking "run" in DrRacket. However, looking more carefully at the stack trace below, I think I've misread it. This dump came from a DrRacket hang (hence the SIGQUIT), and based on my reading of Apple CoreAudio documentation, it looks to me like the call in frame 11 of thread 0 to AudioUnitStop is waiting on a mutex which I'm guessing is held by thread 10, which I believe is the main audio processing thread. The action in thread 0 is triggered by a custodian action, as shown by frame 27 of that thread. Thread 10 is blocked, though. I initially believed it was in the middle of a callback, but looking more carefully, it now seems to me that it was blocked on a queue_callback, which surprises me, because I didn't think that a queue-callback could block. I suppose there has to be *some* synchronization in there, though. If I'm reading this correctly, then the custodian-ness could be a red herring; it could be that any racket thread calling CloseStream or another audio function could cause this problem. If queue_callback can block, I'm not sure how to resolve this. Many thanks for your help, John Process: racket [60140] Path: /Users/clements/plt/bin/racket Identifier: racket Version: ??? (???) Code Type: X86-64 (Native) Parent Process: bash [35088] Date/Time: 2011-09-08 16:08:26.985 -0700 OS Version: Mac OS X 10.6.8 (10K549) Report Version: 6 Exception Type: EXC_CRASH (SIGQUIT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 0 Dispatch queue: com.apple.main-thread Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 libSystem.B.dylib 0x00007fff8a275dc2 semaphore_wait_signal_trap + 10 1 libSystem.B.dylib 0x00007fff8a27b40d pthread_mutex_lock + 469 2 com.apple.audio.CoreAudio 0x00007fff857852f4 CAMutex::Lock() + 58 3 com.apple.audio.CoreAudio 0x00007fff8579ef86 IOA_Device::StartCommandExecution(void**) + 42 4 com.apple.audio.CoreAudio 0x00007fff857a091f HP_Device::ExecuteCommand(HP_Command*) + 75 5 com.apple.audio.CoreAudio 0x00007fff857a5cff HP_HardwarePlugIn_DeviceStop(AudioHardwarePlugInInterface**, unsigned int, int (*)(unsigned int, AudioTimeStamp const*, AudioBufferList const*, AudioTimeStamp const*, AudioBufferList*, AudioTimeStamp const*, void*)) + 121 6 com.apple.audio.CoreAudio 0x00007fff857a5c57 HALPlugIn::DeviceStopIOProc(HALObject const&, int (*)(unsigned int, AudioTimeStamp const*, AudioBufferList const*, AudioTimeStamp const*, AudioBufferList*, AudioTimeStamp const*, void*)) + 25 7 com.apple.audio.CoreAudio 0x00007fff857a5bd8 AudioDeviceStop + 190 8 ...pple.audio.units.Components 0x0000000143726d1a AUGenericOutputEntry + 3062 9 ...pple.audio.units.Components 0x0000000143728d03 AUGenericOutputEntry + 11231 10 ...pple.audio.units.Components 0x000000014372b502 AUHALEntry + 3621 11 ...apple.audio.units.AudioUnit 0x00007fff89fb7d20 AudioOutputUnitStop + 38 12 libportaudio.2.dylib 0x0000000143549ccd StopStream + 189 13 libportaudio.2.dylib 0x000000014354546b Pa_CloseStream + 107 14 Racket 0x000000010028f8ac ffi_call_unix64 + 76 15 Racket 0x00000001002904c4 ffi_call + 644 16 Racket 0x000000010028289b ffi_do_call + 1371 17 Racket 0x000000010005d2b5 scheme_do_eval + 10917 18 Racket 0x000000010005fcdf _scheme_apply_from_native + 95 19 ??? 0x00000001004d789b 0 + 4300044443 20 Racket 0x000000010005ce59 scheme_do_eval + 9801 21 Racket 0x000000010005fb2f _scheme_apply_multi_from_native + 95 22 ??? 0x00000001004d2142 0 + 4300022082 23 Racket 0x000000010005ce59 scheme_do_eval + 9801 24 Racket 0x000000010027d458 ffi_do_callback + 520 25 Racket 0x00000001002907ce ffi_closure_unix64_inner + 462 26 Racket 0x000000010028fa2e ffi_closure_unix64 + 70 27 Racket 0x00000001002649f0 scheme_do_close_managed + 1024 28 Racket 0x00000001002669cb do_close_managed + 11 29 Racket 0x0000000100266b29 scheme_close_managed + 9 30 Racket 0x0000000100266b9f custodian_close_all + 63 31 ??? 0x00000001004dccc5 0 + 4300065989 32 ??? 0x00000001004dcb10 0 + 4300065552 33 ??? 0x00000001004f6dc0 0 + 4300172736 34 ??? 0x00000001013cb5b0 0 + 4315723184 35 ??? 0x00000001004f9700 0 + 4300183296 36 ??? 0x00000001053e1dfb 0 + 4382924283 37 ??? 0x00000001004f9700 0 + 4300183296 38 ??? 0x00000001053e1dfb 0 + 4382924283 39 ??? 0x00000001004f9700 0 + 4300183296 40 ??? 0x00000001004d8a50 0 + 4300048976 41 Racket 0x000000010005ce59 scheme_do_eval + 9801 42 Racket 0x00000001000771c5 scheme_dynamic_wind + 1029 43 Racket 0x0000000100077931 dynamic_wind + 321 44 ??? 0x00000001004d2215 0 + 4300022293 45 ??? 0x00000001013ccaac 0 + 4315728556 46 ??? 0x00000001013ccaac 0 + 4315728556 47 Racket 0x000000010005ce59 scheme_do_eval + 9801 48 Racket 0x00000001000771c5 scheme_dynamic_wind + 1029 49 Racket 0x0000000100077931 dynamic_wind + 321 50 ??? 0x00000001004d2215 0 + 4300022293 51 Racket 0x000000010005ce59 scheme_do_eval + 9801 52 Racket 0x0000000100078b09 scheme_finish_apply_for_prompt + 873 53 Racket 0x0000000100078cdc scheme_apply_for_prompt + 92 54 Racket 0x00000001000854d2 call_with_prompt + 1282 55 ??? 0x00000001004d2215 0 + 4300022293 56 ??? 0x00000001004dd0a0 0 + 4300066976 57 Racket 0x000000010005ce59 scheme_do_eval + 9801 58 Racket 0x00000001000771c5 scheme_dynamic_wind + 1029 59 Racket 0x0000000100077931 dynamic_wind + 321 60 ??? 0x00000001004d2215 0 + 4300022293 61 ??? 0x00000001013ccaac 0 + 4315728556 62 ??? 0x00000001013ccaac 0 + 4315728556 63 Racket 0x000000010005ce59 scheme_do_eval + 9801 64 Racket 0x00000001000771c5 scheme_dynamic_wind + 1029 65 Racket 0x0000000100077931 dynamic_wind + 321 66 ??? 0x00000001004d2215 0 + 4300022293 67 Racket 0x000000010005ce59 scheme_do_eval + 9801 68 Racket 0x0000000100078b09 scheme_finish_apply_for_prompt + 873 69 Racket 0x0000000100078cdc scheme_apply_for_prompt + 92 70 Racket 0x00000001000854d2 call_with_prompt + 1282 71 ??? 0x00000001004d2215 0 + 4300022293 72 Racket 0x000000010005ce59 scheme_do_eval + 9801 73 Racket 0x000000010005fcdf _scheme_apply_from_native + 95 74 ??? 0x00000001004d847c 0 + 4300047484 75 ??? 0x00000001004d2282 0 + 4300022402 76 ??? 0x00000001004d8a50 0 + 4300048976 77 ??? 0x00000001004d8a50 0 + 4300048976 78 ??? 0x00000001004d8a50 0 + 4300048976 79 ??? 0x00000001004d8a50 0 + 4300048976 80 ??? 0x00000001004d8a50 0 + 4300048976 81 ??? 0x00000001004d8a50 0 + 4300048976 82 ??? 0x00000001004d8a50 0 + 4300048976 83 ??? 0x00000001004d8a50 0 + 4300048976 84 ??? 0x00000001004d8a50 0 + 4300048976 85 ??? 0x00000001004d8a50 0 + 4300048976 86 ??? 0x00000001004d8a50 0 + 4300048976 87 ??? 0x00000001004d8a50 0 + 4300048976 88 ??? 0x00000001004d8a50 0 + 4300048976 89 ??? 0x00000001004d8a50 0 + 4300048976 90 ??? 0x00000001004d8a50 0 + 4300048976 91 ??? 0x00000001004d8a50 0 + 4300048976 92 ??? 0x00000001004d8a50 0 + 4300048976 93 ??? 0x00000001004d8a50 0 + 4300048976 94 ??? 0x00000001004d8a50 0 + 4300048976 95 ??? 0x00000001004d8a50 0 + 4300048976 96 ??? 0x00000001004d8a50 0 + 4300048976 97 ??? 0x00000001004d8a50 0 + 4300048976 98 ??? 0x00000001004d8a50 0 + 4300048976 99 ??? 0x00000001004d8a50 0 + 4300048976 100 ??? 0x00000001004d8a50 0 + 4300048976 101 ??? 0x00000001004d8a50 0 + 4300048976 102 ??? 0x00000001004d8a50 0 + 4300048976 103 ??? 0x00000001004dcb10 0 + 4300065552 104 Racket 0x000000010005ce59 scheme_do_eval + 9801 105 Racket 0x0000000100078b09 scheme_finish_apply_for_prompt + 873 106 Racket 0x0000000100078cdc scheme_apply_for_prompt + 92 107 Racket 0x00000001000854d2 call_with_prompt + 1282 108 ??? 0x00000001004d2215 0 + 4300022293 109 Racket 0x000000010005ce59 scheme_do_eval + 9801 110 Racket 0x0000000100078b09 scheme_finish_apply_for_prompt + 873 111 Racket 0x0000000100078cdc scheme_apply_for_prompt + 92 112 Racket 0x00000001000854d2 call_with_prompt + 1282 113 ??? 0x00000001004dccc5 0 + 4300065989 114 Racket 0x000000010005ce59 scheme_do_eval + 9801 115 Racket 0x0000000100070d94 force_values + 292 116 Racket 0x000000010007ae72 scheme_force_value_same_mark + 114 117 ??? 0x00000001004dc719 0 + 4300064537 118 Racket 0x000000010005ce59 scheme_do_eval + 9801 119 Racket 0x000000010005fb2f _scheme_apply_multi_from_native + 95 120 ??? 0x00000001004d2142 0 + 4300022082 121 Racket 0x000000010005ce59 scheme_do_eval + 9801 122 Racket 0x000000010007acf3 apply_k + 179 123 Racket 0x000000010007b986 scheme_top_level_do_worker + 1222 124 racket 0x00000001000033fe finish_cmd_line_run + 3598 125 racket 0x0000000100004051 main_after_stack + 2753 126 Racket 0x000000010000d399 scheme_main_stack_setup + 153 127 racket 0x0000000100001da4 main + 36 128 racket 0x0000000100001d54 start + 52 Thread 1: 0 libSystem.B.dylib 0x00007fff8a275d7a mach_msg_trap + 10 1 libSystem.B.dylib 0x00007fff8a2763ed mach_msg + 59 2 Racket 0x0000000100292826 exception_thread + 134 3 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 4 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 2: 0 libSystem.B.dylib 0x00007fff8a2d799e __sigwait + 10 1 libSystem.B.dylib 0x00007fff8a2d7977 sigwait + 73 2 Racket 0x00000001001a4511 mz_proc_thread_signal_worker + 161 3 Racket 0x00000001001613b0 mzrt_thread_stub + 96 4 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 5 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 3: 0 libSystem.B.dylib 0x00007fff8a2b0a6a __semwait_signal + 10 1 libSystem.B.dylib 0x00007fff8a2b4881 _pthread_cond_wait + 1286 2 Racket 0x00000001001aa294 green_thread_timer + 148 3 Racket 0x00000001001613b0 mzrt_thread_stub + 96 4 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 5 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 4: Dispatch queue: com.apple.libdispatch-manager 0 libSystem.B.dylib 0x00007fff8a28ec0a kevent + 10 1 libSystem.B.dylib 0x00007fff8a290add _dispatch_mgr_invoke + 154 2 libSystem.B.dylib 0x00007fff8a2907b4 _dispatch_queue_invoke + 185 3 libSystem.B.dylib 0x00007fff8a2902de _dispatch_worker_thread2 + 252 4 libSystem.B.dylib 0x00007fff8a28fc08 _pthread_wqthread + 353 5 libSystem.B.dylib 0x00007fff8a28faa5 start_wqthread + 13 Thread 5: com.apple.CFSocket.private 0 libSystem.B.dylib 0x00007fff8a2b9932 select$DARWIN_EXTSN + 10 1 com.apple.CoreFoundation 0x00007fff81482498 __CFSocketManager + 824 2 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 3 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 6: 0 libSystem.B.dylib 0x00007fff8a2b9932 select$DARWIN_EXTSN + 10 1 Racket 0x00000001001b9166 default_sleep + 294 2 Racket 0x0000000100258a6b check_sleep + 1371 3 Racket 0x0000000100263511 scheme_thread_block + 2241 4 Racket 0x0000000100263bfc scheme_block_until + 332 5 Racket 0x00000001002653f5 do_sync + 1173 6 ??? 0x00000001004d2215 0 + 4300022293 7 Racket 0x000000010005ce59 scheme_do_eval + 9801 8 Racket 0x000000010005fb2f _scheme_apply_multi_from_native + 95 9 ??? 0x00000001004d2142 0 + 4300022082 10 Racket 0x000000010005ce59 scheme_do_eval + 9801 11 Racket 0x000000010007acf3 apply_k + 179 12 Racket 0x000000010007b986 scheme_top_level_do_worker + 1222 13 Racket 0x00000001001a9b4d place_start_proc_after_stack + 1373 14 Racket 0x00000001001a9bc4 place_start_proc + 100 15 Racket 0x00000001001613b0 mzrt_thread_stub + 96 16 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 17 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 7: 0 libSystem.B.dylib 0x00007fff8a2b0a6a __semwait_signal + 10 1 libSystem.B.dylib 0x00007fff8a2b4881 _pthread_cond_wait + 1286 2 Racket 0x00000001001aa294 green_thread_timer + 148 3 Racket 0x00000001001613b0 mzrt_thread_stub + 96 4 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 5 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 8: 0 libSystem.B.dylib 0x00007fff8a2b0a6a __semwait_signal + 10 1 libSystem.B.dylib 0x00007fff8a2b4881 _pthread_cond_wait + 1286 2 Racket 0x00000001001aa08b pt_sema_wait + 43 3 Racket 0x00000001001aa0cc do_watch + 28 4 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 5 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 9: 0 libSystem.B.dylib 0x00007fff8a275d7a mach_msg_trap + 10 1 libSystem.B.dylib 0x00007fff8a2763ed mach_msg + 59 2 com.apple.CoreFoundation 0x00007fff81460932 __CFRunLoopRun + 1698 3 com.apple.CoreFoundation 0x00007fff8145fdbf CFRunLoopRunSpecific + 575 4 com.apple.audio.CoreAudio 0x00007fff857b5786 HALRunLoop::OwnThread(void*) + 152 5 com.apple.audio.CoreAudio 0x00007fff857a2755 CAPThread::Entry(CAPThread*) + 125 6 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 7 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13 Thread 10: 0 libSystem.B.dylib 0x00007fff8a2b0a6a __semwait_signal + 10 1 libSystem.B.dylib 0x00007fff8a2b4881 _pthread_cond_wait + 1286 2 Racket 0x0000000100160d0b mzrt_sema_wait + 59 3 Racket 0x000000010027d59f ffi_queue_callback + 175 4 Racket 0x00000001002907ce ffi_closure_unix64_inner + 462 5 Racket 0x000000010028fa2e ffi_closure_unix64 + 70 6 libportaudio.2.dylib 0x00000001435469d0 AdaptingOutputOnlyProcess + 224 7 libportaudio.2.dylib 0x0000000143547398 PaUtil_EndBufferProcessing + 552 8 libportaudio.2.dylib 0x000000014354c3a7 AudioIOProc + 2295 9 ...pple.audio.units.Components 0x000000014372517a 0x14371d000 + 33146 10 ...pple.audio.units.Components 0x000000014372480e 0x14371d000 + 30734 11 ...pple.audio.units.Components 0x0000000143723323 0x14371d000 + 25379 12 ...pple.audio.units.Components 0x000000014372245c 0x14371d000 + 21596 13 ...pple.audio.units.Components 0x0000000143727fd0 AUGenericOutputEntry + 7852 14 com.apple.audio.CoreAudio 0x00007fff857a533d HP_IOProc::Call(AudioTimeStamp const&, AudioTimeStamp const&, AudioBufferList const*, AudioTimeStamp const&, AudioBufferList*) + 313 15 com.apple.audio.CoreAudio 0x00007fff857a510f IOA_Device::CallIOProcs(AudioTimeStamp const&, AudioTimeStamp const&, AudioTimeStamp const&) + 303 16 com.apple.audio.CoreAudio 0x00007fff857a4f45 HP_IOThread::PerformIO(AudioTimeStamp const&, double) + 771 17 com.apple.audio.CoreAudio 0x00007fff857a2f54 HP_IOThread::WorkLoop() + 1832 18 com.apple.audio.CoreAudio 0x00007fff857a2827 HP_IOThread::ThreadEntry(HP_IOThread*) + 9 19 com.apple.audio.CoreAudio 0x00007fff857a2755 CAPThread::Entry(CAPThread*) + 125 20 libSystem.B.dylib 0x00007fff8a2aefd6 _pthread_start + 331 21 libSystem.B.dylib 0x00007fff8a2aee89 thread_start + 13
smime.p7s
Description: S/MIME cryptographic signature
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