Sleepable RCU

Posted Jun 8, 2015 17:47 UTC (Mon) by PaulMcKenney (✭ supporter ✭, #9624)
In reply to: Sleepable RCU by juihaochiang
Parent article: Sleepable RCU

Hello, Jui-Hao,

Suppose we have the following sequence of events:

Task A does srcu_read_lock() and then picks up a pointer to an RCU -protected data element.
Task B removes that same data element from the list.
(Task B is supposed to do synchronize_srcu() here, but let's assume that it fails to do so.)
Task B frees that data element—while Task A is still using it. Chaos ensues.

So that synchronize_srcu() really is needed! Please do not leave it out.

Thanx, Paul