| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Thu, 21 Sep 2017 14:25:13 +0200 |
| Subject: [PATCH] RCU: we need to skip that warning but only on sleeping |
| locks |
| |
| This check is okay for upstream. On RT we trigger this while blocking on |
| sleeping lock. In this case, it is okay to schedule() within a RCU |
| section. |
| Since spin_lock() and read_lock() disables migration it should be okay |
| to test for this as an indication whether or not a sleeping lock is |
| held. The ->pi_blocked_on member won't work becasuse it might also be |
| set on regular mutexes. |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| kernel/rcu/tree_plugin.h | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/kernel/rcu/tree_plugin.h |
| +++ b/kernel/rcu/tree_plugin.h |
| @@ -325,9 +325,13 @@ static void rcu_preempt_note_context_swi |
| struct task_struct *t = current; |
| struct rcu_data *rdp; |
| struct rcu_node *rnp; |
| + int mg_counter = 0; |
| |
| lockdep_assert_irqs_disabled(); |
| - WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0); |
| +#if defined(CONFIG_PREEMPT_COUNT) && defined(CONFIG_SMP) |
| + mg_counter = t->migrate_disable; |
| +#endif |
| + WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !mg_counter); |
| if (t->rcu_read_lock_nesting > 0 && |
| !t->rcu_read_unlock_special.b.blocked) { |
| |
