sync to Linus v4.13-rc2 for subsystem developers to work against

1 files changed, 6 insertions, 2 deletions

diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index f8269036bf0b..52c4e907c14b 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -59,7 +59,11 @@ static void notrace klp_ftrace_handler(unsigned long ip,
 
         ops = container_of(fops, struct klp_ops, fops);
 
-        rcu_read_lock();
+        /*
+         * A variant of synchronize_sched() is used to allow patching functions
+         * where RCU is not watching, see klp_synchronize_transition().
+         */
+        preempt_disable_notrace();
 
         func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
                                       stack_node);
@@ -115,7 +119,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
 
         klp_arch_set_pc(regs, (unsigned long)func->new_func);
 unlock:
-        rcu_read_unlock();
+        preempt_enable_notrace();
 }
 
 /*