Hello, I encounter strange problems with semaphore library from l4env. I use a vanillia revision 230 on an intel PIII architecture. After some debugging and tracing, I get the following scenarion :
1. thread 03 of my process calls a semaphore down timed which then calls BLOCKTIMED IPC to semaphore thread 02. So semaphore structure is: counter = -1 pending = 0 queue = 03 2. thread 08 calls semaphore_up inline assembler code. Before IPC call, the semaphore structure is as follow : counter = 0 pending = 0 queue = 03 3. Thread 03 gains the CPU after timeout and calls IPC RELEASETIMED : counter = 1 pending = 0 queue = empty 4. Thread 02 doesn't find thread into queue, so that pending is set to 1. counter = 1 pending = 1 queue = empty 5. Thread 03 calls semaphore_down. No IPC is called. counter = 0 pending = 1 queue = empty 6. Thread 03 calls semaphore_down again and IPC BLOCK is called. IPC awakes imediately 03 with a counter value of -1 and nobody into queue. counter = -1 pending = 0 queue = empty It seems to me that this state is not normal. Do you agree ? Is this scenario possible as I observe clearly state 4 5 and 6 ? What pending is for ? Thanks in advance for your answers. Marc _______________________________________________ l4-hackers mailing list l4-hackers@os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers
