From: "Paul E. McKenney" <paul...@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 ip6_tnl_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 ACCESS_ONCE() as suggested by Eric Dumazet and Josh Triplett. Reported-by: kbuild test robot <fengguang...@intel.com> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: "David S. Miller" <da...@davemloft.net> Cc: Alexey Kuznetsov <kuz...@ms2.inr.ac.ru> Cc: James Morris <jmor...@namei.org> Cc: Hideaki YOSHIFUJI <yoshf...@linux-ipv6.org> Cc: Patrick McHardy <ka...@trash.net> Cc: net...@vger.kernel.org --- net/ipv6/ip6_tunnel.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 61355f7f4da5..2bea7a4e49ed 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -245,7 +245,8 @@ ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t) (iter = rtnl_dereference(*tp)) != NULL; tp = &iter->next) { if (t == iter) { - rcu_assign_pointer(*tp, t->next); + /* Both --rcu and visible, so ACCESS_ONCE() is OK. */ + ACCESS_ONCE(*tp) = t->next; break; } } -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/