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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-10-24 11:11:08 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-10-29 10:20:08 -0700
commitbbe5d7a93a39104be146f71b9b99af8fb65a6a2d (patch)
tree93b01d8fe8e5a1ce8fa35b43d00213cb58e3a751 /kernel/rcu
parent776d680711f4836964f3005ee53794661ca74629 (diff)
downloadlinux-bbe5d7a93a39104be146f71b9b99af8fb65a6a2d.tar.bz2
rcu: Fix for rcuo online-time-creation reorganization bug
Commit 35ce7f29a44a (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>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_plugin.h10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6d07fb402e84..5053dae4454e 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -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;
- rdp_last = rdp;
- rdp = rdp->nocb_next_follower;
- rdp_last->nocb_next_follower = NULL;
+ 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;
}