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-rw-r--r--include/linux/rcupdate.h19
-rw-r--r--include/linux/srcu.h11
2 files changed, 26 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index f409529ff35a..146d37d31778 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -226,6 +226,15 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head)
}
#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU)
+bool rcu_lockdep_current_cpu_online(void);
+#else /* #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
+static inline bool rcu_lockdep_current_cpu_online(void)
+{
+ return 1;
+}
+#endif /* #else #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
+
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#ifdef CONFIG_PROVE_RCU
@@ -270,6 +279,9 @@ extern int debug_lockdep_rcu_enabled(void);
* occur in the same context, for example, it is illegal to invoke
* rcu_read_unlock() in process context if the matching rcu_read_lock()
* was invoked from within an irq handler.
+ *
+ * Note that rcu_read_lock() is disallowed if the CPU is either idle or
+ * offline from an RCU perspective, so check for those as well.
*/
static inline int rcu_read_lock_held(void)
{
@@ -277,6 +289,8 @@ static inline int rcu_read_lock_held(void)
return 1;
if (rcu_is_cpu_idle())
return 0;
+ if (!rcu_lockdep_current_cpu_online())
+ return 0;
return lock_is_held(&rcu_lock_map);
}
@@ -313,6 +327,9 @@ extern int rcu_read_lock_bh_held(void);
* notice an extended quiescent state to other CPUs that started a grace
* period. Otherwise we would delay any grace period as long as we run in
* the idle task.
+ *
+ * Similarly, we avoid claiming an SRCU read lock held if the current
+ * CPU is offline.
*/
#ifdef CONFIG_PREEMPT_COUNT
static inline int rcu_read_lock_sched_held(void)
@@ -323,6 +340,8 @@ static inline int rcu_read_lock_sched_held(void)
return 1;
if (rcu_is_cpu_idle())
return 0;
+ if (!rcu_lockdep_current_cpu_online())
+ return 0;
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index e1b005918bbb..9a323728e60c 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -99,15 +99,18 @@ long srcu_batches_completed(struct srcu_struct *sp);
* power mode. This way we can notice an extended quiescent state to
* other CPUs that started a grace period. Otherwise we would delay any
* grace period as long as we run in the idle task.
+ *
+ * Similarly, we avoid claiming an SRCU read lock held if the current
+ * CPU is offline.
*/
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
- if (rcu_is_cpu_idle())
- return 0;
-
if (!debug_lockdep_rcu_enabled())
return 1;
-
+ if (rcu_is_cpu_idle())
+ return 0;
+ if (!rcu_lockdep_current_cpu_online())
+ return 0;
return lock_is_held(&sp->dep_map);
}