Re: Kernel hang with latest snapshot

[Li Guanglei <guanglei at cn dot ibm dot com>]

David Boreham wrote:
> Hi, I'm interested in using LKET to analyse the behavior of a large
> application that has disk i/o-bound performance. My top level goal
> is to be able to record system-wide traces of all i/o activity at a
> system call level (open,close,write,fsync etc). I am using Fedora Core 5
> (although if it would help I'd be happy to use any distribution/custom 
> kernel).
>
> The systemtap that comes with the FC5 distribution is too old to
> include LKET. The LKET from the latest systemtap snapshot
> (20061007) does not work with the systemtap binary in the distribution.
>
> So I removed the distribution systemtap, installed the dependencies
> and built/installed the latest snapshot systemtap.
>
> So far so good.
>
> Unfortunately when I try to use LKET it would appear that my
> kernel hangs (machine totally unresponsive after the kernel module
> is loaded).
>
> This is the command line I'm using :
>
> /usr/local/bin/stap -e "probe addevent.iosyscall.flock.* {}" -bM -vv -k

The 2.6.17-1.2187_FC5-i686 debuginfo package is too big to download 
for me :(. But I tried 2.6.18/i686, it works really well. Probing for 
almost half an hour without crash the kernel.

> (btw addevent.iosyscall.* produces C code that will not compile)
>
> It gets this far and then hangs:
>
>  ld -m elf_i386 -m elf_i386 -r -o /tmp/stapA607FG/stap_3312.ko 
> /tmp/stapA607FG/stap_3312.o /tmp/stapA607FG/stap_3312.mod.o
> make: Leaving directory `/usr/src/kernels/2.6.17-1.2187_FC5-i686'
> Pass 4: compiled C into "stap_3312.ko" in 23930usr/2630sys/28585real ms.
> Pass 5: starting run.
> Running sudo /usr/local/bin/staprun -u root -d 3312 
> /tmp/stapA607FG/stap_3312.ko
>
> I'm using this kernel : 2.6.17-1.2187_FC5 (i386/i686) and vmware.
>
> Any advice on how to proceed is most welcome.
>
> Thanks for your time.

I also checked in some bugfix for LKET on i386. I tried to turn on all 
probes(addevent.*) and it works ok. You can try the latest CVS and let 
me know if you have any problem.

- Guanglei