Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 09/13] ipv6/sit: Apply rcu_access_pointer() to avoid sparse false positive | Date | Tue, 24 Sep 2013 18:35:12 -0700 |
| |
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 ipip6_tunnel_unlink() 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 --- net/ipv6/sit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 7ee5cb9..fcb050a 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -157,7 +157,7 @@ static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t) (iter = rtnl_dereference(*tp)) != NULL; tp = &iter->next) { if (t == iter) { - rcu_assign_pointer(*tp, t->next); + rcu_assign_pointer(*tp, rcu_access_pointer(t->next)); break; } } -- 1.8.1.5
| |