Re: [Xenomai] 3.5.7 posix/mprotect failure; "I-pipe: could not find timer" fixed!

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 01/14/2013 05:47 AM, John Morris wrote:

> On 01/13/2013 01:41 PM, Gilles Chanteperdrix wrote:
>> On 01/13/2013 08:14 PM, John Morris wrote:
>>
>>> Hi Gilles and Jan,
>>>
>>> Note change of thread subject.  I'm starting to get confused.
>>>
>>> On 01/13/2013 06:16 AM, Gilles Chanteperdrix wrote:
>>>> On 01/13/2013 05:36 AM, John Morris wrote:
>>>>
>>>>> On 01/12/2013 11:31 AM, Gilles Chanteperdrix wrote:
>>>>>> On 01/12/2013 06:26 PM, John Morris wrote:
>>>>>>> 1)  Most worrisome is "kernel BUG at mm/mmap.c:2313!   invalid opcode:
>>>>>>> 0000 [#2] SMP".  Is this related to HEAPSZ or STACKPOOLSZ?  My mind is
>>>>>>> getting foggy about all the things I've seen, but it seems like it was
>>>>>>> happening earlier in the tests until these config values were quadrupled.
>>>>>>
>>>>>>
>>>>>> Could you check whether you can reproduce this issue with the I-pipe
>>>>>> patch for 3.5.7 ? The next xenomai release will be based on this version
>>>>>> on x86 anyway. Branch for-core-3.5.7 in ipipe-gch.git
>>>>>
>>>>> Different problem; Xenomai wouldn't start:
>>>>>
>>>>>   I-pipe: could not find timer for cpu #0
>>>>>
>>>>> dmesg:
>>>>> http://www.zultron.com/static/2013/01/xenomai/3.5.7-test/foo-dmesg-3.5.7.log
>>>>>
>>>>> .config:
>>>>> www.zultron.com/static/2013/01/xenomai/3.5.7-test/foo-kernel-3.5.7.config
>>>>>
>>>>> FYI, I found this same problem on two of my systems while testing your
>>>>> Debian packages.  Both AMD Athlon II 64-bit (one single, one dual core).
>>>>>  They're about the same generation of motherboards, AM2 or AM2+ socket.
>>>>>  One is AMD 770 chipset, the other NVidia GeForce 6100 / nForce 430.
>>>>>
>>>>> Hardware looks similar to Mariusz's in this post, where he had the same
>>>>> problem:
>>>>>
>>>>> http://www.xenomai.org/pipermail/xenomai/2012-December/027121.html
>>>>>
>>>>> He's also running AMD 64-bit on a Gigabyte motherboard, but the next
>>>>> generation AM3 socket, Phenom CPU, AMD 890 chipset.  I don't have a C1E
>>>>> BIOS option on these boards to enable/disable.  These same motherboards
>>>>> don't suffer this problem with mainline Xenomai on 3.5.3.
>>>>
>>>>
>>>> If you had the same problem as Marius, you would have seen it with
>>>> 3.5.3, and you would get the message in the dmesg about C1E, so, it is
>>>> probably something else. 
>>>
>>> Yes, I'm definitely getting confused.  I did see the same problem with
>>> C1E, but only while running your 3.5.7 .debs, and not in the 3.5.7 el6
>>> packages that are the main subject of this sub-thread:
>>>
>>> http://www.zultron.com/static/2013/01/xenomai/3.5.7-deb-gilles/dmesg-3.5.7-deb-gilles.log
>>
>>
>> Ah, that is because I rebased the I-pipe tree in between, and at some
>> point the code printing the message was wrong (ATOMIC_INIT(0) instead of
>> ATOMIC_INIT(-1)). That is my fault then, sorry.
>>
>>>
>>>> Could you run
>>>>
>>>> cat /proc/timer_list
>>>
>>> Back to el6 again, 3.5.7 i-pipe:
>>>
>>> http://www.zultron.com/static/2013/01/xenomai/3.5.7-test/foo-cat-proc-timer_list-3.5.7-test.log
>>
>>
>> The LAPIC is definitely up and running (mode: 3). So, it probably means
>> that the erratum detection is not sufficient to decide not to use a
>> LAPIC. Checking your logs, we see:
>>
>> using AMD E400 aware idle routine
>>
>> which means the LAPIC could potentially be unusable, but the idle
>> routine also checks for a bit in a K8 specific MSR and prints the message:
>>
>> System has AMD C1E enabled
>>
>> If this bit is set, and in your case the message is not printed so the
>> bit is not set. So, the LAPIC is usable, but due to the changes I made
>> to try and print a message in Marius case, I broke the detection in your
>> case.
>>
>> I have just pushed a rework for this commit in the for-core-3.5.7 branch
>> in ipipe-gch git.
> 
> And it worked, no more C1E error!  Thanks!
> 
> It looks like the AMD-64 AM2/AM2+ socket CPUs were the last generation
> without C1E, and the AM3 socket CPUs were the first gen with.
> 
> Back to the original problem, the posix/mprotect problem is confirmed to
> be in this branch:
> 
>   ++ /usr/lib64/xenomai/regression/posix/mprotect
>   memory read
>   FAILURE: sigdebug_handler triggered, reason 2
>   memory write after exec enable


I will try to compile a kernel with the same configuration as you to see
if I can reproduce the issue.
-- 
                                                                Gilles.