Reproducible unpredictable crash when using Expression selection

Dear Alex,

when using Expression selection, OVITO might unexpectedly crash. Crashes happen at different times but are reproducible.

Tested with OVITO build dev626,dev648 pro (also present in previous builds)

How to reproduce: add expression selection modifier and choose the highest animation speed (as the crash seems to happen randomly). The backtrace might look differently (see the two examples below).

I also attach small test ovito and data files, to make it possible to reproduce the problem accurately:

In case it's a special bug on my hardware/software:

CPU: Intel Xeon E3-1270
OS: Mint 19.3 tricia (Ubuntu 18.04)
Kernel: x86_64 Linux 5.3.0-26-generic

Best regards
Arkadii

gdb backtrace(s): First one: Thread 3447 "ovito" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffc09f2700 (LWP 4766)] __memmove_sse2_unaligned_erms () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:427 427 ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S: No such file or directory. (gdb) bt #0 __memmove_sse2_unaligned_erms () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:427 #1 0x00007ffff4ff2aec in std::string::_Rep::_M_clone(std::allocator const&, unsigned long) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #2 0x00007ffff4ff31dc in std::basic_string, std::allocator >::basic_string(std::string const&) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #3 0x00007fffe92a1f68 in std::vector >::operator=(std::vector > const&) () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #4 0x00007fffe929a34f in Ovito::StdObj::PropertyExpressionEvaluator::Worker::Worker(Ovito::StdObj::PropertyExpressionEvaluator&) () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #5 0x00007fffe929ac5d in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #6 0x00007fffe92a117b in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #7 0x00007ffff4367827 in __pthread_once_slow (once_control=0x13a5cb8, init_routine=0x7ffff4fda830 <__once_proxy>) at pthread_once.c:116 #8 0x00007fffe9299d2e in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #9 0x00007ffff4fdb66f in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #10 0x00007ffff435f6db in start_thread (arg=0x7fffc09f2700) at pthread_create.c:463 #11 0x00007ffff469888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 Second one: Thread 11933 "ovito" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffc1959700 (LWP 1030)] 0x00007ffff4ff2b2b in std::string::_Rep::_M_clone(std::allocator const&, unsigned long) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (gdb) bt #0 0x00007ffff4ff2b2b in std::string::_Rep::_M_clone(std::allocator const&, unsigned long) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #1 0x00007ffff4ff31dc in std::basic_string, std::allocator >::basic_string(std::string const&) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #2 0x00007fffe92a1f68 in std::vector >::operator=(std::vector > const&) () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #3 0x00007fffe929a34f in Ovito::StdObj::PropertyExpressionEvaluator::Worker::Worker(Ovito::StdObj::PropertyExpressionEvaluator&) () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #4 0x00007fffe929ac5d in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #5 0x00007fffe92a117b in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #6 0x00007ffff4367827 in __pthread_once_slow (once_control=0x239b248, init_routine=0x7ffff4fda830 <__once_proxy>) at pthread_once.c:116 #7 0x00007fffe9299d2e in ?? () from /home/arkadii/Downloads/ovito-pro-3.0.0-dev648-x86_64/lib/ovito/plugins/StdObj.so #8 0x00007ffff4fdb66f in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #9 0x00007ffff435f6db in start_thread (arg=0x7fffc1959700) at pthread_create.c:463 #10 0x00007ffff469888f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95