[Jack-Devel] jack2: question about possible race condition

Dear Jack2 Maintainers, I have a question about JackAudioDriver.cpp. It seems to me like there could be a possible race condition in JackAudioDriver::ProcessGraphSyncMaster(), where the driver would do read and write on a slave device without waiting for graph execution end. Below is the proposed "fix", or what I would expect is correct, am I reading something wrong in the code? What do you guys think? diff --git a/common/JackAudioDriver.cpp b/common/JackAudioDriver.cpp index ef7c683..9172fe8 100644 --- a/common/JackAudioDriver.cpp +++ b/common/JackAudioDriver.cpp @@ -327,16 +327,12 @@ void JackAudioDriver::ProcessGraphSyncMaster() // fBeginDateUst is set in the "low level" layer, fEndDateUst is from previous cycle if (fEngine->Process(fBeginDateUst, fEndDateUst)) { - if (ResumeRefNum() < 0) { - jack_error("JackAudioDriver::ProcessGraphSyncMaster: ResumeRefNum error"); - } - if (ProcessReadSlaves() < 0) { jack_error("JackAudioDriver::ProcessGraphSync: ProcessReadSlaves error, engine may now behave abnormally!!"); } - if (ProcessWriteSlaves() < 0) { - jack_error("JackAudioDriver::ProcessGraphSync: ProcessWriteSlaves error, engine may now behave abnormally!!"); + if (ResumeRefNum() < 0) { + jack_error("JackAudioDriver::ProcessGraphSyncMaster: ResumeRefNum error"); } // Waits for graph execution end @@ -344,6 +340,10 @@ void JackAudioDriver::ProcessGraphSyncMaster() jack_error("JackAudioDriver::ProcessGraphSync: SuspendRefNum error, engine may now behave abnormally!!"); } + if (ProcessWriteSlaves() < 0) { + jack_error("JackAudioDriver::ProcessGraphSync: ProcessWriteSlaves error, engine may now behave abnormally!!"); + } + } else { // Graph not finished: do not activate it jack_error("JackAudioDriver::ProcessGraphSync: Process error"); } -- 2.7.4 Best regards Adam Miartus Engineering Software Multimedia (ADITG/ESM) Tel. +49 5121 49 6973