On 01/26/2012 11:36 AM, Jan Kiszka wrote: > On 2012-01-25 19:05, Jan Kiszka wrote: >> On 2012-01-25 18:44, Gilles Chanteperdrix wrote: >>> On 01/25/2012 06:10 PM, Jan Kiszka wrote: >>>> On 2012-01-25 18:02, Gilles Chanteperdrix wrote: >>>>> On 01/25/2012 05:52 PM, Jan Kiszka wrote: >>>>>> On 2012-01-25 17:47, Jan Kiszka wrote: >>>>>>> On 2012-01-25 17:35, Gilles Chanteperdrix wrote: >>>>>>>> On 01/25/2012 05:21 PM, Jan Kiszka wrote: >>>>>>>>> We had two regressions in this code recently. So test all 6 possible >>>>>>>>> SIGDEBUG reasons, or 5 if the watchdog is not available. >>>>>>>> >>>>>>>> Ok for this test, with a few remarks: >>>>>>>> - this is a regression test, so should go to >>>>>>>> src/testsuite/regression(/native), and should be added to the >>>>>>>> xeno-regression-test >>>>>>> >>>>>>> What are unit test for (as they are defined here)? Looks a bit >>>>>>> inconsistent. >>>>> >>>>> I put under "regression" all the tests I have which corresponded to >>>>> things that failed one time or another in xenomai past. Maybe we could >>>>> move unit tests under regression. >>>>> >>>>>>> >>>>>>>> - we already have a regression test for the watchdog called mayday.c, >>>>>>>> which tests the second watchdog action, please merge mayday.c with >>>>>>>> sigdebug.c (mayday.c also allows checking the disassembly of the code >>>>>>>> in >>>>>>>> the mayday page, a nice feature) >>>>>>> >>>>>>> It seems to have failed in that important last discipline. Need to check >>>>>>> why. >>>>>> >>>>>> Because it didn't check the page content for correctness. But that's now >>>>>> done via the new watchdog test. I can keep the debug output, but the >>>>>> watchdog test of mayday looks obsolete to me. Am I missing something? >>>>> >>>>> The watchdog does two things: it first sends a SIGDEBUG, then if the >>>>> application is still spinning, it sends a SIGSEGV. As far as I >>>>> understood, you test tests the first case, and mayday tests the second >>>>> case, so, I agree that mayday should be removed, but whatever it tests >>>>> should be integrated in the sigdebug test. >>>>> >>>> >>>> Err... SIGSEGV is not a feature, it was the bug I fixed today. :) So the >>>> test case actually specified a bug as correct behavior. >>>> >>>> The fallback case is in fact killing the RT task as before. But I'm >>>> unsure right now: will this leave the system always in a clean state >>>> behind? >>> >>> The test case being a test case and doing nothing particular, I do not >>> see what could go wrong. And if something goes wrong, then it needs fixing. >> >> Well, if you kill a RT task while it's running in the kernel, you risk >> inconsistent system states (held mutexex etc.). In this case the task is >> supposed to spin in user space. If that is always safe, let's implement >> the test. > > Had a closer look: These days the two-stage killing is only useful to > catch endless loops in the kernel. User space tasks can't get around > being migrated on watchdog events, even when SIGDEBUG is ignored. > > To trigger the enforced task termination without leaving any broken > states behind, there is one option: rt_task_spin. Surprisingly for me, > it actually spins in the kernel, thus triggers the second level if > waiting long enough. I wonder, though, if that behavior shouldn't be > improved, ie. the spinning loop be closed in user space - which would > take away that option again. > > Thoughts?
You can also call in an infinite loop, a xenomais syscall which causes a switch to primary mode, but fails. -- Gilles. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core