Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
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?

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Philippe Gerum

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?



Tick-based timing is going to be the problem for determining the 
spinning delay, unless we expose it in the vdso on a per-skin basis, 
which won't be pretty.



Jan




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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
On 2012-01-26 12:20, Philippe Gerum wrote:
 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?

 
 Tick-based timing is going to be the problem for determining the
 spinning delay, unless we expose it in the vdso on a per-skin basis,
 which won't be pretty.

I see. But we should possibly add some signal-pending || amok test to
that kernel loop. That would also kill my test design, but it makes
otherwise some sense I guess.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
On 2012-01-26 13:56, Jan Kiszka wrote:
 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?


 Tick-based timing is going to be the problem for determining the
 spinning delay, unless we expose it in the vdso on a per-skin basis,
 which won't be pretty.
 
 I see. But we should possibly add some signal-pending || amok test to
 that kernel loop. That would also kill my test design, but it makes
 otherwise some sense I guess.

I'm thinking of a change like this:

diff --git a/ksrc/skins/native/syscall.c b/ksrc/skins/native/syscall.c
index acf0375..39204b4 100644
--- a/ksrc/skins/native/syscall.c
+++ b/ksrc/skins/native/syscall.c
@@ -1020,13 +1020,21 @@ static int __rt_timer_inquire(struct pt_regs *regs)
 
 static int __rt_timer_spin(struct pt_regs *regs)
 {
+   xnthread_t *thread = xnpod_current_thread();
+   struct task_struct *p = current;
+   RTIME etime;
RTIME ns;
 
if (__xn_safe_copy_from_user(ns, (void __user *)__xn_reg_arg1(regs),
 sizeof(ns)))
return -EFAULT;
 
-   rt_timer_spin(ns);
+   etime = xnarch_get_cpu_tsc() + xnarch_ns_to_tsc(ns);
+   while ((SRTIME)(xnarch_get_cpu_tsc() - etime)  0) {
+   if (signal_pending(p) || xnthread_amok_p(thread))
+   return -EINTR;
+   cpu_relax();
+   }
 
return 0;
 }

Regarding testability of the second watchdog state: We could add a
syscall to sigtest_module e.g which has the current rt_timer_spin
semantics.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Gilles Chanteperdrix
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.

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
On 2012-01-26 15:55, Gilles Chanteperdrix wrote:
 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.

Nope, we would be migrated to secondary on xnthread_amok_p when
returning to user mode. We need a true kernel loop.

Jan.

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
On 2012-01-26 15:36, Jan Kiszka wrote:
 Regarding testability of the second watchdog state: We could add a
 syscall to sigtest_module e.g which has the current rt_timer_spin
 semantics.

Do you think this makes sense? Or some other testing driver?
Then I would go that direction.

Jan

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Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Gilles Chanteperdrix
On 01/26/2012 04:06 PM, Jan Kiszka wrote:
 On 2012-01-26 15:55, Gilles Chanteperdrix wrote:
 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.
 
 Nope, we would be migrated to secondary on xnthread_amok_p when
 returning to user mode. We need a true kernel loop.

But the loop will continue, and the next call to the syscall will cause
the thread to re-switch to primary mode.

-- 
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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-26 Thread Jan Kiszka
On 2012-01-26 16:52, Gilles Chanteperdrix wrote:
 On 01/26/2012 04:06 PM, Jan Kiszka wrote:
 On 2012-01-26 15:55, Gilles Chanteperdrix wrote:
 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.

 Nope, we would be migrated to secondary on xnthread_amok_p when
 returning to user mode. We need a true kernel loop.
 
 But the loop will continue, and the next call to the syscall will cause
 the thread to re-switch to primary mode.

But the watchdog signal pending flag will be cleared on each
migration, thus the watchdog will never enter the second stage.

Jan

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[Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Jan Kiszka
We had two regressions in this code recently. So test all 6 possible
SIGDEBUG reasons, or 5 if the watchdog is not available.

Signed-off-by: Jan Kiszka jan.kis...@siemens.com
---
 src/testsuite/unit/Makefile.am |   16 +++-
 src/testsuite/unit/sigdebug.c  |  233 
 2 files changed, 248 insertions(+), 1 deletions(-)
 create mode 100644 src/testsuite/unit/sigdebug.c

diff --git a/src/testsuite/unit/Makefile.am b/src/testsuite/unit/Makefile.am
index 1bf5d8d..6e8203d 100644
--- a/src/testsuite/unit/Makefile.am
+++ b/src/testsuite/unit/Makefile.am
@@ -11,7 +11,8 @@ test_PROGRAMS = \
cond-torture-posix \
cond-torture-native \
check-vdso \
-   rtdm
+   rtdm \
+   sigdebug
 
 arith_SOURCES = arith.c arith-noinline.c arith-noinline.h
 
@@ -119,3 +120,16 @@ rtdm_LDADD = \
../../skins/native/libnative.la \
../../skins/common/libxenomai.la \
-lpthread -lrt -lm
+
+sigdebug_SOURCES = sigdebug.c
+
+sigdebug_CPPFLAGS = \
+   @XENO_USER_CFLAGS@ \
+   -I$(top_srcdir)/include
+
+sigdebug_LDFLAGS = @XENO_USER_LDFLAGS@
+
+sigdebug_LDADD = \
+   ../../skins/native/libnative.la \
+   ../../skins/common/libxenomai.la \
+   -lpthread -lm
diff --git a/src/testsuite/unit/sigdebug.c b/src/testsuite/unit/sigdebug.c
new file mode 100644
index 000..57d9beb
--- /dev/null
+++ b/src/testsuite/unit/sigdebug.c
@@ -0,0 +1,233 @@
+/*
+ * Functional testing of unwanted domain switch debugging mechanism.
+ *
+ * Copyright (C) Jan Kiszka  jan.kis...@siemens.com
+ *
+ * Released under the terms of GPLv2.
+ */
+
+#include unistd.h
+#include stdlib.h
+#include stdio.h
+#include stdbool.h
+#include string.h
+#include signal.h
+#include fcntl.h
+#include sys/mman.h
+#include pthread.h
+#include rtdk.h
+#include native/task.h
+#include native/mutex.h
+#include native/sem.h
+#include native/timer.h
+
+#define WRITE_TEST_SIZE(4*1024)
+
+unsigned int expected_reason;
+bool sigdebug_received;
+pthread_t rt_task_thread;
+RT_MUTEX prio_invert;
+RT_SEM send_signal;
+char *mem;
+FILE *wd;
+
+static void setup_checkdebug(unsigned int reason)
+{
+   sigdebug_received = false;
+   expected_reason = reason;
+}
+
+static void check_inner(const char *fn, int line, const char *msg,
+   int status, int expected)
+{
+   if (status == expected)
+   return;
+
+   rt_task_set_mode(T_WARNSW, 0, NULL);
+   rt_print_flush_buffers();
+   fprintf(stderr, FAILURE %s:%d: %s returned %d instead of %d - %s\n,
+   fn, line, msg, status, expected, strerror(-status));
+   exit(EXIT_FAILURE);
+}
+
+static void check_sigdebug_inner(const char *fn, int line, const char *reason)
+{
+   if (sigdebug_received)
+   return;
+
+   rt_task_set_mode(T_WARNSW, 0, NULL);
+   rt_print_flush_buffers();
+   fprintf(stderr, FAILURE %s:%d: no %s received\n, fn, line, reason);
+   exit(EXIT_FAILURE);
+}
+
+#define check(msg, status, expected) ({
\
+   int __status = status;  \
+   check_inner(__FUNCTION__, __LINE__, msg, __status, expected);   \
+   __status;   \
+})
+
+#define check_no_error(msg, status) ({ \
+   int __status = status;  \
+   check_inner(__FUNCTION__, __LINE__, msg,\
+   __status  0 ? __status : 0, 0);\
+   __status;   \
+})
+
+#define check_sigdebug_received(reason) do {   \
+   const char *__reason = reason;  \
+   check_sigdebug_inner(__FUNCTION__, __LINE__, __reason); \
+} while (0)
+
+void rt_task_body(void *cookie)
+{
+   RTIME end;
+   int err;
+
+   rt_task_thread = pthread_self();
+
+   rt_printf(syscall\n);
+   setup_checkdebug(SIGDEBUG_MIGRATE_SYSCALL);
+   syscall(-1);
+   check_sigdebug_received(SIGDEBUG_MIGRATE_SYSCALL);
+
+   rt_printf(signal\n);
+   setup_checkdebug(SIGDEBUG_MIGRATE_SIGNAL);
+   err = rt_sem_v(send_signal);
+   check_no_error(rt_sem_v, err);
+   rt_task_sleep(1000LL);
+   check_sigdebug_received(SIGDEBUG_MIGRATE_SIGNAL);
+
+   rt_printf(relaxed mutex owner\n);
+   setup_checkdebug(SIGDEBUG_MIGRATE_PRIOINV);
+   err = rt_mutex_acquire(prio_invert, TM_INFINITE);
+   check(rt_mutex_acquire, err, -EINTR);
+   check_sigdebug_received(SIGDEBUG_MIGRATE_PRIOINV);
+
+
+   rt_printf(page fault\n);
+   setup_checkdebug(SIGDEBUG_MIGRATE_FAULT);
+   rt_task_sleep(0);
+   *mem ^= 0xFF;
+   check_sigdebug_received(SIGDEBUG_MIGRATE_FAULT);
+
+   if (wd) {
+   rt_printf(watchdog\n);
+   

Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Gilles Chanteperdrix
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
- 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)
- please make the watchdog test mandatory by default (adding a command
line option to skip it for instance), the test should fail if the
watchdog is not enabled, because otherwise, it will be easy to forget
testing this feature. The wathdog is enabled by default with xenomai 2.6
anyway.

-- 
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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Jan Kiszka
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.

 - 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.

 - please make the watchdog test mandatory by default (adding a command
 line option to skip it for instance), the test should fail if the
 watchdog is not enabled, because otherwise, it will be easy to forget
 testing this feature. The wathdog is enabled by default with xenomai 2.6
 anyway.

OK.

Jan

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Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Jan Kiszka
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.
 
 - 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?

Jan

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Corporate Competence Center Embedded Linux

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Gilles Chanteperdrix
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.

-- 
Gilles.

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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Gilles Chanteperdrix
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.

-- 
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Re: [Xenomai-core] [PATCH] Add sigdebug unit test

2012-01-25 Thread Jan Kiszka
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.

Jan



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