7.2-PRERELEASE: make process waiting indefinitely

[Oleg V. Nauman]

  Have experienced today strange issue with my fresh RELENG_7 (  
sources from yesterday April 13, userland and kernel in sync ) -  
sometimes some processes stop running without any visible reason. Have  
seen it twice today during KDE compilation - make process just waiting  
for something while nothing else compiles or some other way prevents  
this process from running ( no SIGSTOP performed, no Ctrl-S performed  
on console). Well it possible related to ( or triggered by ) new ports  
compilation feature for SMP machines ( most of KDE port marked as  
MAKE_JOBS_SAFE=yes ) but anyway this stuck process behavior is  
strange. kill -SIGCONT not helps, but it killable ( Ctrl-C helps at  
least )
Well some info related to this process:
procstat -t 63472 output:

   PID    TID COMM             TDNAME           CPU  PRI STATE   WCHAN
63472 100059 make             -                  1   92 sleep   wait

procstat -kk 63472 output:

   PID    TID COMM             TDNAME           KSTACK
63472 100059 make             -                mi_switch+0x2c8  
sleepq_switch+0xd9 sleepq_catch_signals+0x239 sleepq_wait_sig+0x14  
_sleep+0x307 kern_wait+0xa36 wait4+0x3b syscall+0x2b3  
Xint0x80_syscall+0x20

Some related sysctls output:

kern.smp.cpus: 2
kern.smp.disabled: 0
kern.smp.active: 1

uname -msr output:
FreeBSD 7.2-PRERELEASE i386