[PATCH tip/core/rcu 18/18] rcu/nocb: Suppress uninitialized false-positive in nocb_gp_wait()

[Paul E. McKenney]

Some compilers complain that wait_gp_seq might be used uninitialized
in nocb_gp_wait().  This cannot actually happen because when wait_gp_seq
is uninitialized, needwait_gp must be false, which prevents wait_gp_seq
from being used.  But this analysis is apparently beyond some compilers,
so this commit adds a bogus initialization of wait_gp_seq for the sole
purpose of suppressing the false-positive warning.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
 kernel/rcu/tree_plugin.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 1847fffdfa0a..c1dfbac8cd39 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1668,12 +1668,12 @@ static void nocb_gp_wait(struct rcu_data *my_rdp)
 	unsigned long cur_gp_seq;
 	unsigned long flags;
 	bool gotcbs;
-	bool needwait_gp = false;
+	bool needwait_gp = false; // This prevents actual uninitialized use.
 	bool needwake;
 	bool needwake_gp;
 	struct rcu_data *rdp;
 	struct rcu_node *rnp;
-	unsigned long wait_gp_seq;
+	unsigned long wait_gp_seq = 0; // Suppress "use uninitialized" warning.
 
 	/*
 	 * Each pass through the following loop checks for CBs and for the
-- 
2.17.1