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[tip/core/rcu,13/13] bonding/bond_alb.c: Apply rcu_access_pointer() to avoid sparse false positive

Message ID 1380072916-31557-13-git-send-email-paulmck@linux.vnet.ibm.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Paul E. McKenney Sept. 25, 2013, 1:35 a.m. UTC 
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

The sparse checking for rcu_assign_pointer() was recently upgraded
to reject non-__kernel address spaces.  This also rejects __rcu,
which is almost always the right thing to do.  However, the use in
bond_alb_handle_active_change() is legitimate: It is assigning a pointer
to an element from an RCU-protected list, and all elements of this list
are already visible to caller.

This commit therefore silences this false positive by laundering the
pointer using rcu_access_pointer() as suggested by Josh Triplett.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: netdev@vger.kernel.org
---
 drivers/net/bonding/bond_alb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 91f179d..cdd697c 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -1667,7 +1667,8 @@  void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave
 	}
 
 	swap_slave = bond->curr_active_slave;
-	rcu_assign_pointer(bond->curr_active_slave, new_slave);
+	rcu_assign_pointer(bond->curr_active_slave,
+			   rcu_access_pointer(new_slave));
 
 	if (!new_slave || list_empty(&bond->slave_list))
 		return;