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authorAlexander Gordeev <agordeev@redhat.com>2015-06-03 08:18:27 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-07-15 14:45:16 -0700
commita6d77081e266605c9f4d8c11e0ee00468b9dc614 (patch)
treeb9f200361754e95386e1464a6e21ee1346fb0e82 /kernel/rcu/tree.h
parent9618138b09260e3df5af5a0d7bdc8fca010f6a3f (diff)
downloadlinux-sh-a6d77081e266605c9f4d8c11e0ee00468b9dc614.tar.gz
rcu: Limit rcu_state::levelcnt[] to RCU_NUM_LVLS items
Variable rcu_num_lvls is limited by RCU_NUM_LVLS macro. In turn, rcu_state::levelcnt[] array is never accessed beyond rcu_num_lvls. Thus, rcu_state::levelcnt[] is safe to limit to RCU_NUM_LVLS items. Since rcu_num_lvls could be changed during boot (as result of rcutree.rcu_fanout_leaf kernel parameter update) one might assume a new value could overflow the value of RCU_NUM_LVLS. However, that is not the case, since leaf-level fanout is only permitted to increase, resulting in rcu_num_lvls possibly to decrease. Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
-rw-r--r--kernel/rcu/tree.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index f1f4784f9107..a6faae53ea8f 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -443,7 +443,7 @@ do { \
struct rcu_state {
struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */
- u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
+ u32 levelcnt[RCU_NUM_LVLS]; /* # nodes in each level. */
u8 levelspread[RCU_NUM_LVLS]; /* kids/node in each level. */
u8 flavor_mask; /* bit in flavor mask. */
struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */