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-rw-r--r--kernel/rcupdate.c32
1 files changed, 24 insertions, 8 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f3240e9..7784bd2 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();
@@ -214,15 +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.
- * 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_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();