enabling coredumps of rtapi_app uspace

[rmu75]

To debug certain crashes in realtime components it would make sense to enable coredumps. Basically limits need to be set appropriately (e.g. via systemd-coredump), and you need to set sysctl fs.suid_dumpable = 2 to allow dumping of setuid binaries. It looks like uspace_rtapi_app does explicitely enable coredumps.

But there is something puzzling (to me at least): to get the thing to actually dump to disc, I also need to replace

linuxcnc/src/rtapi/uspace_rtapi_app.cc

Line 692 in bd96ca8

raise(sig);

"raise(sig)" with "kill(getpid(), sig);".

Man page says that for singlethreaded apps these 2 instructions are equivalent. rtapi_app usually consists of >=2 threads AFAIU, one running with non-critical priority, and one or more with realtime priority.

I'm not sure where this "kill(getpid(), sig)" is sending the signal, I suspect to the main non-realtime thread, and there the actual core dump can happen.

So if anybody knows what's going on, please chime in.

[rene-dev]

in the last meeting we decided to just change this, as it should not affect anything.