1 files changed, 22 insertions, 6 deletions

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index a23a57a976d1..7784bd216b6a 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -142,10 +142,17 @@ static int rcuhead_fixup_init(void *addr, enum debug_obj_state state)
                  * Ensure that queued callbacks are all executed.
                  * If we detect that we are nested in a RCU read-side critical
                  * section, we should simply fail, otherwise we would deadlock.
+                 * In !PREEMPT configurations, there is no way to tell if we are
+                 * in a RCU read-side critical section or not, so we never
+                 * attempt any fixup and just print a warning.
                  */
+#ifndef CONFIG_PREEMPT
+                WARN_ON_ONCE(1);
+                return 0;
+#endif
                 if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                     irqs_disabled()) {
-                        WARN_ON(1);
+                        WARN_ON_ONCE(1);
                         return 0;
                 }
                 rcu_barrier();
@@ -184,10 +191,17 @@ static int rcuhead_fixup_activate(void *addr, enum debug_obj_state state)
                  * Ensure that queued callbacks are all executed.
                  * If we detect that we are nested in a RCU read-side critical
                  * section, we should simply fail, otherwise we would deadlock.
+                 * In !PREEMPT configurations, there is no way to tell if we are
+                 * in a RCU read-side critical section or not, so we never
+                 * attempt any fixup and just print a warning.
                  */
+#ifndef CONFIG_PREEMPT
+                WARN_ON_ONCE(1);
+                return 0;
+#endif
                 if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                     irqs_disabled()) {
-                        WARN_ON(1);
+                        WARN_ON_ONCE(1);
                         return 0;
                 }
                 rcu_barrier();
@@ -214,14 +228,17 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state)
                  * Ensure that queued callbacks are all executed.
                  * If we detect that we are nested in a RCU read-side critical
                  * section, we should simply fail, otherwise we would deadlock.
+                 * In !PREEMPT configurations, there is no way to tell if we are
+                 * in a RCU read-side critical section or not, so we never
+                 * attempt any fixup and just print a warning.
                  */
 #ifndef CONFIG_PREEMPT
-                WARN_ON(1);
+                WARN_ON_ONCE(1);
                 return 0;
-#else
+#endif
                 if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                     irqs_disabled()) {
-                        WARN_ON(1);
+                        WARN_ON_ONCE(1);
                         return 0;
                 }
                 rcu_barrier();
@@ -229,7 +246,6 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state)
                 rcu_barrier_bh();
                 debug_object_free(head, &rcuhead_debug_descr);
                 return 1;
-#endif
         default:
                 return 0;
         }