On an SMP x86 with 2 SMT-enabled atom 330 cores  (4 logical CPUs)

Problem is reproducible every time in all kernel releases from 2.6.37.6
up to 2.6.39-rc5,  but no problem in 2.6.36,  and no problem if I omit the --callgraph=2 option

My opcontrol command lines :

(First I set ksrcdir to my kernel build directory like so)
ksrcdir= symlink target of /lib/modules/`uname -r`/source

then

opcontrol --init;
opcontrol --setup --vmlinux=${ksrcdir}/vmlinux --separate=cpu --callgraph=2;
opcontrol --start-daemon --vmlinux=${ksrcdir}/vmlinux;
opcontrol --start --separate=cpu;

OOPS occurs soon after.    The OOPS offset is at the line reading
         addr = *stack;
and register EBX (which contains value of stack) is garbaged  -   0x0000000a


I see some other mentions of similar problems elsewhere,  but they are
all for much older kernels,  and in my case the above commands work fine
on 23.6.36

John Lumby
-------------------------
output of ver_linux

Linux lumbyont.localdomain 2.6.39-rc5 #5 SMP Tue May 3 11:04:57 EDT 2011
i686 GNU/Linux

Gnu C                  4.4.4
Gnu make               3.81
binutils               2.19.1
util-linux             2.13-pre7
mount                  support
module-init-tools      3.3-pre1
e2fsprogs              1.41.13
pcmciautils            014
quota-tools            3.13.
PPP                    2.4.4
isdn4k-utils           3.9
Linux C Library        2.11.1
Dynamic linker (ldd)   2.11.1
Procps                 3.2.7
Net-tools              1.60
Kbd                    1.12
oprofile               0.9.7git
Sh-utils               8.9
udev                   095
wireless-tools         29
Modules Loaded         xt_NFLOG nfnetlink_log nfnetlink ppp_synctty
ppp_async crc_ccitt ppp_generic slhc via_rhine snd_hda_intel
snd_hda_codec rtc_cmos rtc_core rtc_lib bridge stp llc i915
drm_kms_helper intel_agp intel_gtt tun xt_state ipt_MASQUERADE
iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 dm_mod
parport_pc lp parport