[asterisk-users] puzzle

[Jeff LaCoursiere]

On Wed, 19 Nov 2008, Tzafrir Cohen wrote:

> On Wed, Nov 19, 2008 at 07:57:33PM +0000, Jeff LaCoursiere wrote:
>>
>> ast% ps auxw | grep modprobe
>> root     17744 99.9  0.0  2688  412 ?        RN   Nov03 23223:01 modprobe
>> -r ipt_state
>
> modprobe -r is basically rmmod . rmmod and insmod and nowdays mostly
> wrappers to kernel code.
>
> So while an strace of that process might give some more information
> about it, I believe that the kernel-level backtrace would be more
> interesting.
>
> For that, try either the 'p' or 't' sysrq commands. 'p' gives a stack
> trace of the current process. 't': of all the processes. You can give a
> sysrq command either through the console (on x86: alt-sysrq-<key>) or:
>
>  echo <key> >/proc/sysrq-trigger

No access to the console, sadly, so I tried the trigger method:

[root at ast init.d]# echo p > /proc/sysrq-trigger

which resulted in a single line in /var/log/messages:

Nov 19 14:51:10 ast kernel: SysRq : Show Regs

I waited a few minutes, then tried the 't':

[root at ast init.d]# echo t > /proc/sysrq-trigger

which seemed to hang, so I killed it about thirty seconds later, and now 
my /var/log/messages has 20,000 extra lines :):)

I grepped for the PID and found this:

Nov 19 14:52:40 ast kernel: modprobe      R running  2988 17744      1 
31140 28078 (NOTLB)

The next line started with 'sshd', so I guess there was no trace with 
this?


> BTW: what kernel? What ditsribution?

Keep in mind it has been running almost 1000 days ;)

[root at ast init.d]# uname -a
Linux ast.jbtelenet.com 2.6.9-22.0.2.ELsmp #1 SMP Thu Jan 5 17:13:01 EST 
2006 i686 i686 i386 GNU/Linux

I believe it is Redhat 9.  Its a colo...

Thanks for the interesting debug pointers!

j