tetragon: Change uprobe spec

[olsajiri]

Currently we define uprobe with path/symbol path, which not
handy when you have more symbols from single path to probe.

Changing the spec so the uprobe is defined by path and array
of symbols, like:

 spec:
   uprobes:
   - path: /bin/bash
     symbols:
     - "_start"
     - "main"
       "builtin_help"

TracingPolicy: Replace symbol field (string) with symbols (array of strings) in uprobe spec. If using policies with uprobes, you need to replace the symbol field.

[mtardy]

Hey, what was the motivation behind this? I guess it's a bit similar to what we do in kprobe with list, but also a bit different.

Could you update the documentation on uprobe as well? :)

[olsajiri]

Hey, what was the motivation behind this? I guess it's a bit similar to what we do in kprobe with list, but also a bit different.

it matches the kernel interface where you register symbols for given path/binary
and also the common usecase is to register more symbols for binary, so the current
implementation is bit cumbersome because you always need to specify binary/path
for each symbol

Could you update the documentation on uprobe as well? :)

yep.. I was checking on that, but we did not add any so far,
so there was nothing to fix ;-) I'll add some paragraph

[mtardy]

Hey, what was the motivation behind this? I guess it's a bit similar to what we do in kprobe with list, but also a bit different.

it matches the kernel interface where you register symbols for given path/binary and also the common usecase is to register more symbols for binary, so the current implementation is bit cumbersome because you always need to specify binary/path for each symbol

Could you update the documentation on uprobe as well? :)

yep.. I was checking on that, but we did not add any so far, so there was nothing to fix ;-) I'll add some paragraph

Cool thanks for the details. It was just added indeed, it's still very limited so it should be quick to update, https://tetragon.io/docs/concepts/tracing-policy/hooks/#uprobes.

[jrfastab]

well the generate stuff is fun.

[lambdanis]

Hey, replacing a required field in the CRD is a breaking change. Technically this should mean moving to v1alpha2 I believe. But at the very least it should be documented.

@olsajiri could you add a release note instructing users how to upgrade? It would be nice to update the examples too.