4.18-stable patches

added patches:
	rcu-make-expedited-gps-handle-cpu-0-being-offline.patch

diff --git a/queue-4.18/rcu-make-expedited-gps-handle-cpu-0-being-offline.patch b/queue-4.18/rcu-make-expedited-gps-handle-cpu-0-being-offline.patch
new file mode 100644 (file)
index 0000000..94f1d41
--- /dev/null
+++ b/queue-4.18/rcu-make-expedited-gps-handle-cpu-0-being-offline.patch
@@ -0,0 +1,57 @@
+From fcc63543650150629c8a873cbef3578770acecd9 Mon Sep 17 00:00:00 2001
+From: Boqun Feng <boqun.feng@gmail.com>
+Date: Fri, 15 Jun 2018 12:06:31 -0700
+Subject: rcu: Make expedited GPs handle CPU 0 being offline
+
+From: Boqun Feng <boqun.feng@gmail.com>
+
+commit fcc63543650150629c8a873cbef3578770acecd9 upstream.
+
+Currently, the parallelized initialization of expedited grace periods uses
+the workqueue associated with each rcu_node structure's ->grplo field.
+This works fine unless that CPU is offline.  This commit therefore uses
+the CPU corresponding to the lowest-numbered online CPU, or just queues
+the work on WORK_CPU_UNBOUND if there are no online CPUs corresponding
+to this rcu_node structure.
+
+Note that this patch uses cpu_is_offline() instead of the usual approach
+of checking bits in the rcu_node structure's ->qsmaskinitnext field.  This
+is safe because preemption is disabled across both the cpu_is_offline()
+check and the call to queue_work_on().
+
+Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
+[ paulmck: Disable preemption to close offline race window. ]
+Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+[ paulmck: Apply Peter Zijlstra feedback on CPU selection. ]
+Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/rcu/tree_exp.h |    9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+--- a/kernel/rcu/tree_exp.h
++++ b/kernel/rcu/tree_exp.h
+@@ -472,6 +472,7 @@ retry_ipi:
+ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
+                                    smp_call_func_t func)
+ {
++      int cpu;
+       struct rcu_node *rnp;
+ 
+       trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("reset"));
+@@ -492,7 +493,13 @@ static void sync_rcu_exp_select_cpus(str
+                       continue;
+               }
+               INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus);
+-              queue_work_on(rnp->grplo, rcu_par_gp_wq, &rnp->rew.rew_work);
++              preempt_disable();
++              cpu = cpumask_next(rnp->grplo - 1, cpu_online_mask);
++              /* If all offline, queue the work on an unbound CPU. */
++              if (unlikely(cpu > rnp->grphi))
++                      cpu = WORK_CPU_UNBOUND;
++              queue_work_on(cpu, rcu_par_gp_wq, &rnp->rew.rew_work);
++              preempt_enable();
+               rnp->exp_need_flush = true;
+       }
+ 

diff --git a/queue-4.18/series b/queue-4.18/series
new file mode 100644 (file)
index 0000000..1c7b6cb
--- /dev/null
+++ b/queue-4.18/series
@@ -0,0 +1 @@
+rcu-make-expedited-gps-handle-cpu-0-being-offline.patch

diff --git a/queue-4.9/series b/queue-4.9/series
new file mode 100644 (file)
index 0000000..e69de29