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authorAlexander Gordeev <agordeev@redhat.com>2015-07-09 15:34:23 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-07-17 14:58:40 -0700
commit032dfc87225c96ec1771e5967436c4b23d1dc5d6 (patch)
treeb37db4952f1bd658f7d7a62683aa94ae4b45417f /kernel/rcu/tree.h
parent426216970e0458c1f507860f4837cbde66a72263 (diff)
downloadlinux-sh-032dfc87225c96ec1771e5967436c4b23d1dc5d6.tar.gz
rcu: Shut up bogus gcc array bounds warning
Because gcc does not realize a loop would not be entered ever (i.e. in case of rcu_num_lvls == 1): for (i = 1; i < rcu_num_lvls; i++) rsp->level[i] = rsp->level[i - 1] + levelcnt[i - 1]; some compiler (pre- 5.x?) versions give a bogus warning: kernel/rcu/tree.c: In function ‘rcu_init_one.isra.55’: kernel/rcu/tree.c:4108:13: warning: array subscript is above array bounds [-Warray-bounds] rsp->level[i] = rsp->level[i - 1] + rsp->levelcnt[i - 1]; ^ Fix that warning by adding an extra item to rcu_state::level[] array. Once the bogus warning is fixed in gcc and kernel drops support of older versions, the dummy item may be removed from the array. Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Suggested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> 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.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 581f8d3c5b28..faee5242d6ff 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -443,7 +443,9 @@ do { \
*/
struct rcu_state {
struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
- struct rcu_node *level[RCU_NUM_LVLS]; /* Hierarchy levels. */
+ struct rcu_node *level[RCU_NUM_LVLS + 1];
+ /* Hierarchy levels (+1 to */
+ /* shut bogus gcc warning) */
u8 flavor_mask; /* bit in flavor mask. */
struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
void (*call)(struct rcu_head *head, /* call_rcu() flavor. */