I'm Paolo Minazzi and some time ago I write you for a problem
related to xenomai and gdb.
After a long time I think to be near to a solution.
I'd like your help and opinions because maybe also other people
have the same problem.
In short, if I debug a xenomai user-space application,
sometimes after a rt_task_sleep the application seems locked.
After this condition, I have to restart my arm processor
because xenomai seems locked. Normal linux application instead
continue to work correctly.
A solution that works for me is to comment some lines in
xenomai-2.5.6/ksrc/nucleus/shadow.c:2620
Please see my comments that begin with "// COMMENT"
==================================================================================
if (xnthread_test_state(next, XNDEBUG)) {
if (signal_pending(next_task)) {
sigset_t pending;
/*
* Do not grab the sighand lock here:
* it's useless, and we already own
* the runqueue lock, so this would
* expose us to deadlock situations on
* SMP.
*/
wrap_get_sigpending(&pending, next_task);
// COMMENT if (sigismember(&pending, SIGSTOP) ||
// COMMENT sigismember(&pending, SIGINT))
// COMMENT goto no_ptrace;
}
xnthread_clear_state(next, XNDEBUG);
unlock_timers();
}
no_ptrace:
==================================================================================
The source of my problem seems to be the locked timers.
If I unlock the timers (manually using a dirty hack) when I'm in the bug
condition
I can repeair the problem and continue to use xenomai without any problems.
In xenomai-2.5.6/ksrc/nucleus/shadow.c:2615
/*
* Check whether we need to unlock the timers, each
* time a Linux task resumes from a stopped state,
* excluding tasks resuming shortly for entering a
* stopped state asap due to ptracing. To identify the
* latter, we need to check for SIGSTOP and SIGINT in
* order to encompass both the NPTL and LinuxThreads
* behaviours.
*/
that explains why SIGINT and SIGSTOP are checked. I do not understand well
all this but it seems related to signal used by gdb.
Have you got an idea to solve in the right way the problem ?
Thanks for your time
Paolo Minazzi
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