Building net/citrix_ica freezes the system (netbsd-6)

[Aleksey Cheusov <cheusov%tut.by@localhost>]

System: netbsd-6/i386 as of 2012-06-16.

Building net/citrix_ica package which uses Linux emulation
inside chroot partially freezes my two core system.
"Partially" means that most X application don't react on mouse buttons
and keyboard.
Ctrl-Alt-Fn works fine and I'm able to login as root and run some command.
top(1) says that "[system]" eats 100% cpu of one CPU core.
I entered ddb and generate a crashdump for the kernel.
It's probably useless but stacktrace is below.

I believe this problem is 100% reproducible
but it doesn't happen immediately, but
a few minutes after cd net/citrix_ica; make package.

GENERIC was built with debugging info, so I'm able to analyse the crashdump.

Any help?

#0  0xc05ba748 in maybe_dump (howto=260) at
/srv/src_netbsd6/sys/arch/i386/i386/machdep.c:878
878                     dumpsys();
#0  0xc05ba748 in maybe_dump (howto=260) at
/srv/src_netbsd6/sys/arch/i386/i386/machdep.c:878
#1  cpu_reboot (howto=260, bootstr=0x0) at
/srv/src_netbsd6/sys/arch/i386/i386/machdep.c:899
#2  0xc07a4eba in vpanic (fmt=0xc01003d1 "cpu_switchto: switching
above IPL_SCHED (%d)", ap=0xda8ea914 "\b") at
/srv/src_netbsd6/sys/kern/subr_prf.c:308
#3  0xc07a4f5f in panic (fmt=0xc01003d1 "cpu_switchto: switching above
IPL_SCHED (%d)") at /srv/src_netbsd6/sys/kern/subr_prf.c:205
#4  0xc01003ce in ?? ()
#5  0xc055724f in sleepq_block (timo=0, catch=false) at
/srv/src_netbsd6/sys/kern/kern_sleepq.c:261
#6  0xc0528910 in cv_wait (cv=0xc0c9a504, mtx=0xc0c9a500) at
/srv/src_netbsd6/sys/kern/kern_condvar.c:216
#7  0xc07ac2c2 in xc_lowpri (ci=0xc34b6000, arg2=0x0, arg1=0xc34b6000,
func=0xc05299a0 <cpu_xc_offline>) at
/srv/src_netbsd6/sys/kern/subr_xcall.c:257
#8  xc_unicast (flags=0, func=0xc05299a0 <cpu_xc_offline>,
arg1=0xc34b6000, arg2=0x0, ci=0xc34b6000) at
/srv/src_netbsd6/sys/kern/subr_xcall.c:206
#9  0xc052a013 in cpu_setstate (ci=0xc34b6000, online=false) at
/srv/src_netbsd6/sys/kern/kern_cpu.c:433
#10 0xc026c7d9 in cpu_stop (dv=<optimized out>) at
/srv/src_netbsd6/sys/arch/x86/x86/cpu.c:1111
#11 0xc0545bf7 in shutdown_all (how=256) at
/srv/src_netbsd6/sys/kern/kern_pmf.c:369
#12 pmf_system_shutdown (how=256) at /srv/src_netbsd6/sys/kern/kern_pmf.c:385
#13 0xc05ba773 in cpu_reboot (howto=256, bootstr=0x0) at
/srv/src_netbsd6/sys/arch/i386/i386/machdep.c:928
#14 0xc028d855 in db_sync_cmd (addr=-1060511132, have_addr=false,
count=-1060511131, modif=0xda8eab8c "d\342\311\300") at
/srv/src_netbsd6/sys/ddb/db_command.c:1375
#15 0xc028df5a in db_command (last_cmdp=0xc0c2e41c) at
/srv/src_netbsd6/sys/ddb/db_command.c:908
#16 0xc028e2db in db_command_loop () at
/srv/src_netbsd6/sys/ddb/db_command.c:566
#17 0xc0293d38 in db_trap (type=1, code=0) at
/srv/src_netbsd6/sys/ddb/db_trap.c:90
#18 0xc0290c92 in kdb_trap (type=1, code=0, regs=0xda8eadec) at
/srv/src_netbsd6/sys/arch/i386/i386/db_interface.c:241
#19 0xc07f819c in trap (frame=0xda8eadec) at
/srv/src_netbsd6/sys/arch/i386/i386/trap.c:385
#20 0xc010d08f in ?? ()
#21 0xc08ff925 in internal_command (ksym2=<optimized out>,
ksym=<optimized out>, type=<optimized out>, sc=0x6) at
/srv/src_netbsd6/sys/dev/wscons/wskbd.c:1589
#22 wskbd_translate (id=0xc0cc9a80, type=2, value=<optimized out>) at
/srv/src_netbsd6/sys/dev/wscons/wskbd.c:1717
#23 0xc08ffc67 in wskbd_input (dev=0xc3681200, type=2, value=1) at
/srv/src_netbsd6/sys/dev/wscons/wskbd.c:682
#24 0xc066a92f in pckbd_input (vsc=0xc3661f80, data=1) at
/srv/src_netbsd6/sys/dev/pckbport/pckbd.c:585
#25 0xc066991b in pckbcintr (vsc=0xc34aec40) at
/srv/src_netbsd6/sys/dev/ic/pckbc.c:597
#26 0xc04c6ed0 in intr_biglock_wrapper (vp=0xc365c8c8) at
/srv/src_netbsd6/sys/arch/x86/x86/intr.c:605
#27 0xc01035f1 in ?? ()