processes hanging in _umtx_op

[Dale Hagglund]

While experimenting with gnuradio and latest packages for
openoffice.org-3, I've run across a situation where a process hangs in
the _umtx_op system call.  The process can't be interrupted with SIGINT,
but SIGQUIT kills it and generates a core dump.

I can reproduce this reliably with

        $ python -c "import wx"

I'm running 7.0-RELEASE-p2 with "uname -a" giving the following output,
suitably wrapped.

        FreeBSD ponoka.ab.hsia.telus.net
        7.0-RELEASE-p2 FreeBSD 7.0-RELEASE-p2
        #0: Wed Jun 18 07:33:20 UTC 2008
        root at i386-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC
        i386

I won't be at all surprised if this is some strange library
compatibility problem I've introduced over time, but I'm at a loss as to
how to track the problem further.  I've attached the final few lines of
the kdump output from the command above, and I can provide my current
list of packages if necessary.

Any advice or suggestions would be appreciated.

Dale Hagglund

------------------------- start: kdump output -------------------------
 34453 python   1223164746.661828 CALL  munmap(0x2aa00000,0xc1000)
 34453 python   1223164746.661840 RET   munmap 0
 34453 python   1223164746.662541 CALL  _umtx_op(0x283071e0,0x8,0x1,0x283071c0,0
)
 34453 python   1223164752.019372 RET   _umtx_op -1 errno 4 Interrupted system c
all
 34453 python   1223164752.019433 PSIG  SIGINT caught handler=0x80d8020 mask=0x0
 code=0x0
 34453 python   1223164752.019454 CALL  getpid
 34453 python   1223164752.019460 RET   getpid 34453/0x8695
 34453 python   1223164752.019471 CALL  sigaction(SIGINT,0xbfbfaf3c,0xbfbfaf24)
 34453 python   1223164752.019480 RET   sigaction 0
 34453 python   1223164752.019487 CALL  sigreturn(0xbfbfafa0)
 34453 python   1223164752.019497 RET   sigreturn JUSTRETURN
 34453 python   1223164752.019511 CALL  _umtx_op(0x283071e0,0x8,0x1,0x283071c0,0
)
 34453 python   1223164752.856485 RET   _umtx_op -1 errno 4 Interrupted system c
all
 34453 python   1223164752.856550 PSIG  SIGINT caught handler=0x80d8020 mask=0x0
 code=0x0
 34453 python   1223164752.856571 CALL  getpid
 34453 python   1223164752.856577 RET   getpid 34453/0x8695
 34453 python   1223164752.856587 CALL  sigaction(SIGINT,0xbfbfaf3c,0xbfbfaf24)
 34453 python   1223164752.856597 RET   sigaction 0
 34453 python   1223164752.856604 CALL  sigreturn(0xbfbfafa0)
 34453 python   1223164752.856613 RET   sigreturn JUSTRETURN
 34453 python   1223164752.856628 CALL  _umtx_op(0x283071e0,0x8,0x1,0x283071c0,0
)
 34453 python   1223164753.425922 RET   _umtx_op -1 errno 4 Interrupted system c
all
 34453 python   1223164753.425984 PSIG  SIGQUIT SIG_DFL
 34453 python   1223164753.425997 NAMI  "python.core"
------------------------- end: kdump output -------------------------