rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPT
The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the
fixup actions. So just produce a warning from !PREEMPT.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f3240e9..b54d6d1 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -142,7 +142,14 @@
* 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);
+ return 0;
+#endif
if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
irqs_disabled()) {
WARN_ON(1);
@@ -184,7 +191,14 @@
* 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);
+ return 0;
+#endif
if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
irqs_disabled()) {
WARN_ON(1);
@@ -214,12 +228,14 @@
* 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.
- * Note that the machinery to reliably determine whether
- * or not we are in an RCU read-side critical section
- * exists only in the preemptible RCU implementations
- * (TINY_PREEMPT_RCU and TREE_PREEMPT_RCU), which is why
- * DEBUG_OBJECTS_RCU_HEAD is disallowed if !PREEMPT.
+ * 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);
+ return 0;
+#endif
if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
irqs_disabled()) {
WARN_ON(1);