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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-01-21 15:26:03 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-03-03 11:16:00 -0800
commitd24209bb689e2c7f7418faec9b4a948e922d24da (patch)
tree40db37902a30acb68f5733e666f25ea7b52e8485 /include/linux/lockdep.h
parent6629240575992a6f0d18c46f5160b34527b0e501 (diff)
rcu: Improve diagnostics for blocked critical sections in irq
If an RCU read-side critical section occurs within an interrupt handler or a softirq handler, it cannot have been preempted. Therefore, there is a check in rcu_read_unlock_special() checking for this error. However, when this check triggers, it lacks diagnostic information. This commit therefore moves rcu_read_unlock()'s lockdep annotation to follow the call to __rcu_read_unlock() and changes rcu_read_unlock_special()'s WARN_ON_ONCE() to an lockdep_rcu_suspicious() in order to locate where the offending RCU read-side critical section began. In addition, the value of the ->rcu_read_unlock_special field is printed. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/lockdep.h')
-rw-r--r--include/linux/lockdep.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 74ab23176e9b..066ba4157541 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -531,8 +531,13 @@ do { \
# define might_lock_read(lock) do { } while (0)
#endif
-#ifdef CONFIG_PROVE_RCU
+#ifdef CONFIG_LOCKDEP
void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
+#else
+static inline void
+lockdep_rcu_suspicious(const char *file, const int line, const char *s)
+{
+}
#endif
#endif /* __LINUX_LOCKDEP_H */