Commit bbe5d7a9 authored Oct 24, 2014 by Paul E. McKenney

rcu: Fix for rcuo online-time-creation reorganization bug

Commit 35ce7f29 (rcu: Create rcuo kthreads only for onlined CPUs)
contains checks for the case where CPUs are brought online out of
order, re-wiring the rcuo leader-follower relationships as needed.
Unfortunately, this rewiring was broken. This apparently went undetected
due to the tendency of systems to bring CPUs online in order. This commit
nevertheless fixes the rewiring.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent 776d6807

kernel/rcu/tree_plugin.h

+7 −3

Original line number	Diff line number	Diff line
		@@ -2586,9 +2586,13 @@ static void rcu_spawn_one_nocb_kthread(struct rcu_state *rsp, int cpu)
		rdp->nocb_leader = rdp_spawn;
		if (rdp_last && rdp != rdp_spawn)
		rdp_last->nocb_next_follower = rdp;
		if (rdp == rdp_spawn) {
		rdp = rdp->nocb_next_follower;
		} else {
		rdp_last = rdp;
		rdp = rdp->nocb_next_follower;
		rdp_last->nocb_next_follower = NULL;
		}
		} while (rdp);
		rdp_spawn->nocb_next_follower = rdp_old_leader;
		}