rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros

This commit adds a lockdep_assert_irqs_disabled() call to the
helper macros that release the rcu_node structure's ->lock, namely
to raw_spin_unlock_rcu_node(), raw_spin_unlock_irq_rcu_node() and
raw_spin_unlock_irqrestore_rcu_node().  The point of this is to help track
down a situation where lockdep appears to be insisting that interrupts
are enabled while holding an rcu_node structure's ->lock.

Link: https://lore.kernel.org/lkml/20201111133813.GA81547@elver.google.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index e01cba5..839f5be 100644 (file)
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -378,7 +378,11 @@ do {                                                                       \
        smp_mb__after_unlock_lock();                                    \
 } while (0)
 
-#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock))
+#define raw_spin_unlock_rcu_node(p)                                    \
+do {                                                                   \
+       lockdep_assert_irqs_disabled();                                 \
+       raw_spin_unlock(&ACCESS_PRIVATE(p, lock));                      \
+} while (0)
 
 #define raw_spin_lock_irq_rcu_node(p)                                  \
 do {                                                                   \
@@ -387,7 +391,10 @@ do {                                                                       \
 } while (0)
 
 #define raw_spin_unlock_irq_rcu_node(p)                                        \
-       raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock))
+do {                                                                   \
+       lockdep_assert_irqs_disabled();                                 \
+       raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock));                  \
+} while (0)
 
 #define raw_spin_lock_irqsave_rcu_node(p, flags)                       \
 do {                                                                   \
@@ -396,7 +403,10 @@ do {                                                                       \
 } while (0)
 
 #define raw_spin_unlock_irqrestore_rcu_node(p, flags)                  \
-       raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)
+do {                                                                   \
+       lockdep_assert_irqs_disabled();                                 \
+       raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags);    \
+} while (0)
 
 #define raw_spin_trylock_rcu_node(p)                                   \
 ({                                                                     \