From: Paul E. McKenney <paulmck@kernel.org>
Date: Wed, 18 Sep 2019 17:10:31 +0000 (-0700)
Subject: rcu: Suppress levelspread uninitialized messages
X-Git-Tag: v5.5-rc1~150^2^2^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=36b5dae64513b7ce3a0e0f6cb469e0f74bacad45;p=thirdparty%2Fkernel%2Flinux.git

rcu: Suppress levelspread uninitialized messages

New tools bring new warnings, and with v5.3 comes:

kernel/rcu/srcutree.c: warning: 'levelspread[<U aa0>]' may be used uninitialized in this function [-Wuninitialized]:  => 121:34

This commit suppresses this warning by initializing the full array
to INT_MIN, which will result in failures should any out-of-bounds
references appear.

Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
---

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 8fd4f82c9b3d7..b64c707f60655 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -299,6 +299,8 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
 {
 	int i;
 
+	for (i = 0; i < RCU_NUM_LVLS; i++)
+		levelspread[i] = INT_MIN;
 	if (rcu_fanout_exact) {
 		levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
 		for (i = rcu_num_lvls - 2; i >= 0; i--)