Thanks for this @Repetier. Just want to sat that this needs to be posted as a troubleshooting tip for investigating server crashes. Especially the repetitive ones!
GDB gave me the following output and this allowed be to resolve the connection issue I had with the failing printer. Turns out it was trying to connect to the same printer. System reboot had readdressed the /dev/ttyUSB* devices.
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[LWP 11831 exited]
--Type <RET> for more, q to quit, c to continue without paging--
Thread 15 "PRT Ender3_S1" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 11731]
0x00197190 in repetier::PrinterState::analyseResponse(std::cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned char&) ()
(gdb) bt
#0 0x00197190 in repetier::PrinterState::analyseResponse(std::cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned char&) ()
#1 0x00000000 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
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