Il 09/05/2013 15.36, Philippe Gerum ha scritto:
On 05/08/2013 06:10 PM, Philippe Gerum wrote:
On 05/08/2013 06:06 PM, Philippe Gerum wrote:
On 05/08/2013 04:30 PM, Paolo Minazzi wrote:
I think to be very near to the solution of this problem.
Thanks to Gilles for his patience.
Now I will retry to make a summary of the problem.
<snip>
The thread 1 finds thread 70 in debug mode !
Which is expected. thread 70 has to be scheduled in with no pending
ptrace signals for leaving this mode, and this may happen long after
the truckload of other threads releases the CPU.
My patch adjust this problem.
I realize that it is a very special case, but it is my case.
I'd like to know if the patch is valid or can be written in a different
way.
For example, I could insert my patch directly in xnpod_delete_thread().
The function unlock_timers() cannot be called from
xenomai-2.5.6/ksrc/skins/native/task.c
because it is defined static. This is a detail. There are simple ways to
solve this.
No, really the patch is wrong, but what you expose does reveal a bug
in the Xenomai core for sure. As Gilles told you, you would be only
papering over that real bug, which would likely show up in a different
situation.
First we need to check for a lock imbalance, I don't think that code
is particularly safe.
I mean a lock imbalance introduced by an unexpected race between the
locking/unlocking calls. The assertions introduced by this patch might
help detecting this, with some luck.
Could you apply that patch below, and report whether some task triggers
the message it introduces, when things go wrong with gdb? TIA,
diff --git a/ksrc/nucleus/pod.c b/ksrc/nucleus/pod.c
index 868f98f..2da3265 100644
--- a/ksrc/nucleus/pod.c
+++ b/ksrc/nucleus/pod.c
@@ -1215,6 +1215,10 @@ void xnpod_delete_thread(xnthread_t *thread)
#else /* !CONFIG_XENO_HW_UNLOCKED_SWITCH */
} else {
#endif /* !CONFIG_XENO_HW_UNLOCKED_SWITCH */
+ if (xnthread_test_state(thread, XNSHADOW|XNMAPPED) == XNSHADOW)
+ printk(KERN_WARNING "%s: deleting unmapped shadow %s\n",
+ __func__, thread->name);
+
xnpod_run_hooks(&nkpod->tdeleteq, thread, "DELETE");
xnsched_forget(thread);
I have tried but no messages on the console.
This time I'm sure. To be sure I have added other messages and I see them.
Paolo
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