Kernel panics during execution of timeouts.stp example when booted with kgdboc=kms,kbd

[dmitry.krivenok@emc.com]

Hi Folks,
I'm new to Systemtap, but already found it very useful and even solved some real problems using it.
Thanks a lot for a great tool!

There is, however, one serious problem I found on two systems
1) Fedora-16 with 3.1.2-1.fc16.x86_64 kernel
2) Arch Linux with vanilla 3.1 kernel

The problem is that kernel panics if you run it with "kgdboc=kms,kbd" parameter and then run standard timeout.stp example as follows:

$ sudo stap -v `locate timeout.stp`
Pass 1: parsed user script and 77 library script(s) using 78192virt/22076res/2376shr kb, in 190usr/60sys/689real ms.
Pass 2: analyzed script: 12 probe(s), 7 function(s), 5 embed(s), 10 global(s) using 202032virt/44892res/3256shr kb, in 790usr/4810sys/10056real ms.
Pass 3: using cached /root/.systemtap/cache/dd/stap_ddd8c5ac8daf0d8644742908043722b3_12685.c
Pass 4: using cached /root/.systemtap/cache/dd/stap_ddd8c5ac8daf0d8644742908043722b3_12685.ko
Pass 5: starting run.

I also tried to run stap with -vvv options and the last lines I saw were:
...
...
execing: /usr/local/libexec/systemtap/stapio -v -v -R stap_ddd8c5ac8daf0d8644742908043722b3_1_777
stapio:parse_modpath:368 modpath="/lib/modules/3.1.1/systemtap/stap_ddd8c5ac8daf0d8644742908043722b3_1_777.ko"
stapio:main:41 modpath="/lib/modules/3.1.1/systemtap/stap_ddd8c5ac8daf0d8644742908043722b3_1_777.ko", modname="stap_ddd8c5ac8daf0d8644742908043722b3_1_777"
stapio:init_stapio:338 init_stapio
stapio:init_ctl_channel:31 Opened /sys/kernel/debug/systemtap/stap_ddd8c5ac8daf0d8644742908043722b3_1_777/.cmd (3)
stapio:stp_main_loop:529 in main loop
stapio:init_relayfs:239 initializing relayfs
stapio:init_relayfs:263 attempting to open /sys/kernel/debug/systemtap/stap_ddd8c5ac8daf0d8644742908043722b3_1_777/trace0
stapio:init_relayfs:263 attempting to open /sys/kernel/debug/systemtap/stap_ddd8c5ac8daf0d8644742908043722b3_1_777/trace1
stapio:init_relayfs:269 ncpus=1, bulkmode = 0
stapio:init_relayfs:352 starting threads

The problem is 100% reproducible on both systems.
I'm not sure if it's a bug in Systemtap or kernel, because I could misconfigure something.

Could someone please try to reproduce the problem and post results here?
Just boot your kernel with "kgdboc=kms,kbd" and run standard example timeouts.stp.

Thanks in advance!

--
Dmitry V. Krivenok
EMC, USD - Entry platforms, CSX group
36/40 Sredny pr. VO
St.Petersburg, 199004, Russia
Phone: +7 812 325 4633 Ext 809
Fax: +7 812 325 4607
Cell: +7 921 576 70 91