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Subject[PATCH tip/core/rcu 25/47] rcu: Make rcu_sleep_check() also check rcu_lock_map
Date
From: "Paul E. McKenney" <paul.mckenney@linaro.org>

Although it is OK to be preempted in an RCU read-side critical section
for TREE_PREEMPT_RCU, it is definitely not OK to be preempted, block,
or might_sleep() within an RCU read-side critical section for TREE_RCU.
Unfortunately, rcu_might_sleep() currently only checks for RCU-bh and
RCU-sched read-side critical sections. This commit therefore makes
rcu_might_sleep() check for RCU read-side critical sections, but only
in TREE_RCU builds.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/rcupdate.h | 14 ++++++++++++++
1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a67d5f1..6df0ae1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -381,8 +381,22 @@ extern int rcu_my_thread_group_empty(void);
} \
} while (0)

+#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
+static inline void rcu_preempt_sleep_check(void)
+{
+ rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
+ "Illegal context switch in RCU read-side "
+ "critical section");
+}
+#else /* #ifdef CONFIG_PROVE_RCU */
+static inline void rcu_preempt_sleep_check(void)
+{
+}
+#endif /* #else #ifdef CONFIG_PROVE_RCU */
+
#define rcu_sleep_check() \
do { \
+ rcu_preempt_sleep_check(); \
rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map), \
"Illegal context switch in RCU-bh" \
" read-side critical section"); \
--
1.7.8


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