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Commit 44c3d0c1 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6: fix a lockdep splat 



Silence lockdep false positive about rcu_dereference() being
used in the wrong context.

First one should use rcu_dereference_protected() as we own the spinlock.

Second one should be a normal assignation, as no barrier is needed.

Fixes: 18367681 ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.")
Reported-by: default avatarDave Jones <davej@codemonkey.org.uk>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 415e3d3e

net/ipv6/ip6_flowlabel.c

+3 −2
Original line number Diff line number Diff line
@@ -540,12 +540,13 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) 
		}

		spin_lock_bh(&ip6_sk_fl_lock);

		for (sflp = &np->ipv6_fl_list;

		     (sfl = rcu_dereference(*sflp)) != NULL;

		     (sfl = rcu_dereference_protected(*sflp,

						      lockdep_is_held(&ip6_sk_fl_lock))) != NULL;

		     sflp = &sfl->next) {

			if (sfl->fl->label == freq.flr_label) {

				if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))

					np->flow_label &= ~IPV6_FLOWLABEL_MASK;

				*sflp = rcu_dereference(sfl->next);

				*sflp = sfl->next;

				spin_unlock_bh(&ip6_sk_fl_lock);

				fl_release(sfl->fl);

				kfree_rcu(sfl, rcu);