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Subject[tip: core/rcu] rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros
The following commit has been merged into the core/rcu branch of tip:

Commit-ID: 7dffe01765d9309b8bd5505503933ec0ec53d192
Gitweb: https://git.kernel.org/tip/7dffe01765d9309b8bd5505503933ec0ec53d192
Author: Paul E. McKenney <paulmck@kernel.org>
AuthorDate: Thu, 19 Nov 2020 13:30:33 -08:00
Committer: Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Mon, 04 Jan 2021 15:54:49 -08:00

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>
---
kernel/rcu/rcu.h | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index e01cba5..839f5be 100644
--- 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) \
({ \
\
 
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