[Pkg-tigervnc-devel] Bug#932499: tigervnc-standalone-server: does not start in buster on arm64

[Bernhard Übelacker]

Control: fixed -1 tigervnc/1.9.0+dfsg-1


Dear Maintainer,
I tried to have another look at it and collected some more details.

I found version 1.9.0+dfsg-1 did not suffer from this crash
(and had no dependency to libunwind8).

I wondered how there the exception handling worked there and found
that e.g. _Unwind_RaiseException is supplied from libgcc_s.so.1,
while in the crashing process it is called in libunwind8.

Therefore another workaround is by forcing the load of libgcc_s.so.1
before libunwind8 by using LD_PRELOAD.

   LD_PRELOAD=/lib/aarch64-linux-gnu/libgcc_s.so.1 /usr/bin/Xtigervnc :1 -desktop debian:1 -auth /home/benutzer/.Xauthority -geometry 1024x600 -depth 16 -rfbwait 30000 -rfbauth /home/benutzer/.vnc/passwd -rfbport 5901 -pn -localhost -SecurityTypes VncAuth

Before I had experimented with the git version of libunwind and
pointing LD_LIBRARY_PATH to it. This did also not crash as long as
libunwind got configured without the switch --enable-cxx-exceptions.
Without that switch the resulting library has no _Unwind_RaiseException,
therefore also the function from libgcc_s.so.1 is used.

In the end I still think libunwind8 is causing this,
but until this is fixed, tigervnc might consider dropping the
dependency at aarch64 and configure with --disable-libunwind.

Kind regards,
Bernhard