lockup: detect the blocker for process hang in RCU grace period

[richl9]

Add a new feature in lockup to look for potential blocker (hogging a CPU for too long and RCU cannot go through) for process hang in RCU grace period

[biger410]

Thanks Richard for creating this. I put some comments in the commit and also looks like ci test is failing, please address that as well.

[richl9]

Thanks Richard for creating this. I put some comments in the commit and also looks like ci test is failing, please address that as well.

Thanks a lot for the comments. I have addressed them accordingly. As for the failed ci test, I think it just simply timed-out (as we are searching particular frame names across all stack traces).

[biger410]

Looks good.