Linux emulation instability

[Alexander Leidinger]

Quoting Doug Barton <dougb at FreeBSD.org> (from Tue, 06 Mar 2007  
15:10:40 -0800):

> Alexander Leidinger wrote:
>> Quoting Doug Barton <dougb at FreeBSD.org> (from Mon, 05 Mar 2007   
>> 16:05:29 -0800):
>>
>>> compat.linux.osrelease: 2.4.2
>>>
>>> Based on your description, and the fact that you're running with
>>> ULE+libthr but with UP, I'd be pretty comfortable saying an SMP problem
>>> is "likely" at this point. If someone wants to come up with some
>>> patches that will likely help the futex+SMP problem, I'll be glad to
>>> test them. Otherwise further testing on my part will have to wait till
>>> I get some more spare cycles.
>>
>> I would be surprised if 2.6.x features like futexes are used with   
>> 2.4.2. We don't disable futexes with 2.4.2, but some 2.6.x features  
>>  are disabled and the glibc of linux_base-fc4 doesn't switch to   
>> using 2.6.x features when osrelease is set to 2.4.2. Additionally   
>> futexes are not fully implemented on amd64 (at least not in HEAD).
>>
>> Also you should not focus on libthr, as it is not used for linux stuff.
>
> Thanks for clearing that up. Would switching to a different linux_base
> port, and/or setting compat.linux.osrelease to something else be a

There are two possibilities for osrelease in our kernel. The default  
and some 2.6.x value. In the Linux glibc as used in our default  
linux_base port there may be other possibilites. Depending on  
osrelease the glibc makes use of different syscalls.

I don't know if using a different linux_base port would give us an  
useful hint what is going on. At least it would narrow it down to  
glibc (or some other lib).

> useful exercise? This is thunderbird 2.0b2, so it may be expecting 2.6
> stuff that we're not giving it, which may be why it's crashing.

You should see a panic string, as Roman has some KASSERTs for this  
case. I'm not sure if this covers everything. Roman?

>> It would be interesting to know where linux-thunderbird locks up.   
>> With a ktrace and maybe the output of linuxulator debugging   
>> messages we may be able to narrow this down to the real problem.
>
> Ok, ktrace I can handle, what kind of debugging needs to be set for the
> linuxulator?

You can't use the FreeBSD kdump, you have to use linux_kdump. A  
package is available at http://www.Leidinger.net/FreeBSD/ for i386  
(you need a different linux_base port than the default to compile it).

Set compat.linux.debug=all, you have to compile (the module) with  
-DDEBUG to get it.

Bye,
Alexander.

-- 
Hi Jimbo.  Dennis.  Really appreciate the help on the income tax.
You wanna help on the audit now?

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