fix: handle capset_x missing thread_info

[adduali1310]

Signed-off-by: Adnan Ali adduali1310@hotmail.com

What type of PR is this?
/kind bug

Any specific area of the project related to this PR?
/area libsinsp

What this PR does / why we need it:
This PR adds a safety check to validate if thread information is available before trying to dereference it when parsing the capset_exit event.
Should be a straightforward change and follows other such checks within the code file as mentioned in the issue.

Which issue(s) this PR fixes:
Fixes #817

Does this PR introduce a user-facing change?:
NONE

[poiana]

Welcome @adduali1310! It looks like this is your first PR to falcosecurity/libs 🎉

[loresuso]

/lgtm

[poiana]

LGTM label has been added.

Git tree hash: 81bb41e9299124c899b100cae8b8e4325f314237

[Andreagit97]

@adduali1310 thank you very much for that, nice catch!
/approve

[FedeDP]

Thank you! Great finding!
/approve

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adduali1310, Andreagit97, FedeDP, loresuso

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [Andreagit97,FedeDP]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[FedeDP]

I think this is suitable for
/milestone 0.10.0

[poiana]

@FedeDP: The provided milestone is not valid for this repository. Milestones in this repository: [0.11.0, next-driver]

Use /milestone clear to clear the milestone.

In response to this:

I think this is suitable for
/milestone 0.10.0

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[adduali1310]

/release-note-none