qemu-arm-static bug in signal handling causes mono and java to hang

Note, this bug is already reported to debian, but it seems to also affect the upstream code.
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=748043

running mono in a chroot environment with qemu-user-static is not posible
because at least one signal used during termination of mono is routed to the
host.

This can be reproduced by:
debootstrap --include=mono-runtime --foreign --arch=armel "wheezy" "mono-test" "http://ftp.de.debian.org//debian"
cp /usr/bin/qemu-arm-static mono-test/usr/bin
mount -t proc none mono-test/proc
mount -o bind /dev mono-test/dev
mount -o bind /sys mono-test/sys
chroot mono-test
../debootstrap/debootstrap --second-stage
exit
mount -t proc none mono-test/proc
mount -o bind /sys mono-test/sys
chroot mono-test
QEMU_STRACE=1 /usr/bin/mono /usr/lib/mono/4.0/gacutil.exe

This will block on a futex:

--8<--
18663 sched_yield(0,0,2582980,0,0,2582928) = 0
18663 clock_gettime(1,-150996384,2,1,2585016,2585600) = 0
18663 tgkill(18663,18664,30,18664,30,-161951744) = 0
18663 futex(0x00293774,FUTEX_PRIVATE_FLAG|FUTEX_WAIT,0,NULL,NULL,0)
--8<--

If you use mono within strace on a native x86 box you can see, that signals
between threads are used during termination:

strace -f -o log.txt /usr/bin/mono /usr/lib/mono/4.0/gacutil.exe

--8<--
14075 sched_yield() = 0
14075 tgkill(14075, 14083, SIGPWR) = 0
14075 futex(0x983f00, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
14083 <... futex resumed> ) = ? ERESTARTSYS (To be restarted)
14083 --- SIGPWR (Power failure) @ 0 (0) ---
14083 futex(0x983f00, FUTEX_WAKE_PRIVATE, 1) = 1
14075 <... futex resumed> ) = 0
14083 rt_sigsuspend(~[INT QUIT ABRT TERM XCPU RTMIN RT_1] <unfinished ...>
14075 futex(0x94d9a4, FUTEX_CMP_REQUEUE_PRIVATE, 1, 2147483647, 0x94da20, 24) = 3
14078 <... futex resumed> ) = 0
14078 futex(0x94da20, FUTEX_WAKE_PRIVATE, 1) = 1
14077 <... futex resumed> ) = 0
14075 futex(0x94d9a4, FUTEX_CMP_REQUEUE_PRIVATE, 1, 2147483647, 0x94da20, 26 <unfinished ...>
--8<--

This also blocks the installation of libnunit2.6-cil within a armel chroot,
because it uses mono in its postinst script.
E.g. (/usr/bin/mono /usr/share/mono/MonoGetAssemblyName.exe /usr/lib/cli/nunit.core-2.6/nunit.core.dll)

Obviously the same as described in:
http://lists.opensuse.org/opensuse-arm/2011-12/msg00000.html
is happening here.

There is an openSuSE patch against qemu:
https://build.opensuse.org/package/view_file/Virtualization:Qemu/qemu/0002-XXX-work-around-SA_RESTART-race-wit.patch?expand=1

This patch also applies against qemu from backports-wheezy and resolves this
issue.

As it seems, that this issue is not Debian specific i will also report it to
the qemu project and reference this bug report.