rcu: Fix local_irq_disable() CONFIG_PROVE_RCU=y false positives
It is documented that local_irq_disable() also delimits RCU_SCHED
read-site critical sections.
See the document of synchronize_sched() or
Documentation/RCU/whatisRCU.txt.
So we have to test irqs_disabled() in rcu_read_lock_sched_held().
Otherwise rcu-lockdep brings incorrect complaint.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <1268940334-10892-1-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index e1bdc4b..872a98e1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -149,7 +149,7 @@
return 1;
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
- return lockdep_opinion || preempt_count() != 0;
+ return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
}
#else /* #ifdef CONFIG_PREEMPT */
static inline int rcu_read_lock_sched_held(void)
@@ -180,7 +180,7 @@
#ifdef CONFIG_PREEMPT
static inline int rcu_read_lock_sched_held(void)
{
- return !rcu_scheduler_active || preempt_count() != 0;
+ return !rcu_scheduler_active || preempt_count() != 0 || irqs_disabled();
}
#else /* #ifdef CONFIG_PREEMPT */
static inline int rcu_read_lock_sched_held(void)