Warning: This probably isn't the best way to do it, and probably isn't even such a good idea. I'm by no means a perlguts adept. Take this one with a pillar of salt.

You might find the DB backtrace method useful, since it (seems to) give you immediate data on the call stack.

Update: You might also want to have a look at caller, which looks like it might do the right thing if called inside package DB. Thanks Zaxo for the idea.

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:wq