To stir up the past.

To stir up past events.

To stir up past events.

To dig up (some) dirt.

Meaning:
Sharing juicy information with others.
A good novel tells us the truth about its hero; but a bad novel tells us the truth about its author.

Care about your friends. Sometimes they fight a battle they don’t tell you about.

To tell old stories / to stir up past events / to stir up the past / to dig up (some) dirt.

Meaning: starting or starting again about something (unpleasant) that happened in the past / bringing up unpleasant, almost forgotten events / reliving old long-forgotten cases, disputes or grievances.