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Re: stracing login process with systemd?


On Fri, Feb 22, 2019 at 08:22:22AM +0100, Eduard Bloch wrote:
> I had some exchange with the maintainer in the BTS but so far that's not
> really fruitful. I would like to just strace the whole login process
> (console or xdm) and check what's happening there around systemd
> invocation, and what's failing.
> Does anyone know how to insert strace or any similar tracing utility?

Don't get your hopes high.
One of the (mis)features of systemd is to ptrace(2) starting services,
thus rendering "I'll just strace/ltrace the thing" classic technique
completely useless.

> I can imagine that one could try to use kernel tracing here but that
> would be a huge hammer.

"perf trace" could work for you.
Attaching to a getty via gdb could work too, but it'll likely screw the
login process.