image/svg+xml ... and this ordering ... Given this ordering ... .... RCU guarantees this ordering. rcu_read_lock() MemoryReference X0 MemoryReference W0 MemoryReference X1 synchronize_rcu() MemoryReference Y0 rcu_read_unlock() P0() P1() rcu_read_lock() MemoryReference Z0 MemoryReference Y1 rcu_read_unlock() P2() ... and this ordering ... MemoryReference Z1 synchronize_rcu() MemoryReference W1 P3() .