balsini/sched-deadline-spy

Kernel module which, for each SCHED_DEADLINE scheduled process, creates a new readable /proc/sched_deadline/[PID], showing tasks' execution information

sched-deadline-spy's Issues

Wrong access to shared variable

Because of the asynchronous nature of the functions contained in the module, it's needed a way to provide mutual exclusion.

The entities involved are:

• data: list of tasks statistics
• writer: jprobed kernel functions
• reader: sequential file writing function

Unfortunately, using mutexes inside a scheduler function may result in a deadlock, so another approach is required.

Maybe, looking at ftrace code may be a good idea to understand how it solved the problem.