net/twinkle stuck in _umtx_op syscall

Gentlemen,

I had trouble running twinkle back on 6-STABLE but now on -CURRENT it's
similar. A ktrace of the session reveals the following

  4019 twinkle  0.000273 CALL  gettimeofday(0xbf2f7cec,0)
  4019 twinkle  0.000009 RET   gettimeofday 0
  4019 twinkle  0.000518 CALL  sigprocmask(SIG_BLOCK,0,0x29e09508)
  4019 twinkle  0.000009 RET   sigprocmask 0
  4019 twinkle  0.000067 CALL  ioctl(0x8,FIONREAD,0xbf2f7bb8)
  4019 twinkle  0.000017 RET   ioctl 0
  4019 twinkle  0.000015 CALL  ioctl(0x8,FIONREAD,0xbf2f7ba8)
  4019 twinkle  0.000015 RET   ioctl 0
  4019 twinkle  0.000143 CALL  ioctl(0x8,FIONREAD,0xbf2f7b38)
  4019 twinkle  0.000016 RET   ioctl 0
  4019 twinkle  0.000007 CALL  ioctl(0x8,FIONREAD,0xbf2f7b28)
  4019 twinkle  0.000005 RET   ioctl 0
  4019 twinkle  0.000006 CALL  ioctl(0x8,FIONREAD,0xbf2f7b28)
  4019 twinkle  0.000014 RET   ioctl 0
  4019 twinkle  0.000011 CALL  ioctl(0x8,FIONREAD,0xbf2f7b18)
  4019 twinkle  0.000006 RET   ioctl 0
  4019 twinkle  0.000014 CALL  _umtx_op(0x2a2e7e80,0x5,0,0,0)
  4019 twinkle  0.001670 RET   _umtx_op 0
  4019 twinkle  0.000013 CALL  getitimer(0,0xbf6fbf4c)
  4019 twinkle  0.000005 RET   getitimer 0
  4019 twinkle  0.000023 CALL  _umtx_op(0x29e1985c,0x2,0,0,0)
  4019 twinkle  4.361916 RET   _umtx_op -1 errno 4 Interrupted system call
  4019 twinkle  0.000044 PSIG  SIGKILL SIG_DFL

It can only be killed -9 and will otherwise stick in _umtx_op() forever.
Any clue from the threading guys on what tricks I should try?

My libmap.conf is emtpy, twinkle is linked against the following
binaries:

/usr/local/bin/twinkle:
        libsndfile.so.1 => /usr/local/lib/libsndfile.so.1 (0x283a0000)
        libccext2-1.5.so.0 => /usr/local/lib/libccext2-1.5.so.0 (0x283ff000)
        libgnutls.so.15 => /usr/local/lib/libgnutls.so.15 (0x28441000)
        libgcrypt.so.13 => /usr/local/lib/libgcrypt.so.13 (0x284bb000)
        libz.so.4 => /lib/libz.so.4 (0x2850a000)
        libccrtp1-1.5.so.0 => /usr/local/lib/libccrtp1-1.5.so.0 (0x2851c000)
        libccgnu2-1.5.so.0 => /usr/local/lib/libccgnu2-1.5.so.0 (0x28542000)
        librt.so.1 => /usr/lib/librt.so.1 (0x28594000)
        libkdecore.so.6 => /usr/local/lib/libkdecore.so.6 (0x28599000)
        libkdeui.so.6 => /usr/local/lib/libkdeui.so.6 (0x287d3000)
        libkabc.so.3 => /usr/local/lib/libkabc.so.3 (0x28aaa000)
        libspeex.so.1 => /usr/local/lib/libspeex.so.1 (0x28b5d000)
        libilbc.so.0 => /usr/local/lib/libilbc.so.0 (0x28b7d000)
        libzrtpcpp-0.9.so.0 => /usr/local/lib/libzrtpcpp-0.9.so.0 (0x28b8c000)
        libboost_regex.so => /usr/local/lib/libboost_regex.so (0x28bab000)
        libqt-mt.so.3 => /usr/local/lib/libqt-mt.so.3 (0x28c39000)
        libXext.so.6 => /usr/local/lib/libXext.so.6 (0x2930b000)
        libX11.so.6 => /usr/local/lib/libX11.so.6 (0x29319000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x29405000)
        libm.so.5 => /lib/libm.so.5 (0x294ed000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x29503000)
        libthr.so.3 => /lib/libthr.so.3 (0x2950e000)
        libc.so.7 => /lib/libc.so.7 (0x29521000)
        libFLAC.so.7 => /usr/local/lib/libFLAC.so.7 (0x29623000)
        libgpg-error.so.0 => /usr/local/lib/libgpg-error.so.0 (0x29656000)
        libintl.so.8 => /usr/local/lib/libintl.so.8 (0x2965a000)
        libiconv.so.3 => /usr/local/lib/libiconv.so.3 (0x29663000)
        libDCOP.so.6 => /usr/local/lib/libDCOP.so.6 (0x29751000)
        libutil.so.7 => /lib/libutil.so.7 (0x29783000)
        libart_lgpl_2.so.5 => /usr/local/lib/libart_lgpl_2.so.5 (0x29790000)
        libidn.so.16 => /usr/local/lib/libidn.so.16 (0x297a6000)
        libkdefx.so.6 => /usr/local/lib/libkdefx.so.6 (0x297d7000)
        libjpeg.so.9 => /usr/local/lib/libjpeg.so.9 (0x297ff000)
        libvcard.so.0 => /usr/local/lib/libvcard.so.0 (0x2981e000)
        libkio.so.6 => /usr/local/lib/libkio.so.6 (0x29842000)
        libkresources.so.3 => /usr/local/lib/libkresources.so.3 (0x29b82000)
        libmng.so.1 => /usr/local/lib/libmng.so.1 (0x29ba4000)
        libpng.so.5 => /usr/local/lib/libpng.so.5 (0x29c05000)
        libXi.so.6 => /usr/local/lib/libXi.so.6 (0x29c2a000)
        libXrender.so.1 => /usr/local/lib/libXrender.so.1 (0x29c32000)
        libXrandr.so.2 => /usr/local/lib/libXrandr.so.2 (0x29c3a000)
        libXcursor.so.1 => /usr/local/lib/libXcursor.so.1 (0x29c41000)
        libXinerama.so.1 => /usr/local/lib/libXinerama.so.1 (0x29c4a000)
        libXft.so.2 => /usr/local/lib/libXft.so.2 (0x29c4d000)
        libfreetype.so.9 => /usr/local/lib/libfreetype.so.9 (0x29c5f000)
        libfontconfig.so.1 => /usr/local/lib/libfontconfig.so.1 (0x29cc9000)
        libSM.so.6 => /usr/local/lib/libSM.so.6 (0x29cf3000)
        libICE.so.6 => /usr/local/lib/libICE.so.6 (0x29cfc000)
        libXau.so.6 => /usr/local/lib/libXau.so.6 (0x29d13000)
        libXdmcp.so.6 => /usr/local/lib/libXdmcp.so.6 (0x29d16000)
        librpcsvc.so.4 => /usr/lib/librpcsvc.so.4 (0x29d1b000)
        libkdesu.so.6 => /usr/local/lib/libkdesu.so.6 (0x29d24000)
        libkwalletclient.so.1 => /usr/local/lib/libkwalletclient.so.1 (0x29d3c000)
        libfam.so.0 => /usr/local/lib/libfam.so.0 (0x29d4d000)
        liblcms.so.1 => /usr/local/lib/liblcms.so.1 (0x29d55000)
        libXfixes.so.3 => /usr/local/lib/libXfixes.so.3 (0x29d84000)
        libexpat.so.6 => /usr/local/lib/libexpat.so.6 (0x29d89000)


Cheers,
Ulrich Spoerlein
-- 
"It is better to remain silent and be thought a fool,
than to speak, and remove all doubt."