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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: 18367681a1 ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2016-02-02 17:55:01 -08:00 committed by David S. Miller
parent 415e3d3e90
commit 44c3d0c1c0
1 changed files with 3 additions and 2 deletions
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5
net/ipv6/ip6_flowlabel.c
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@ -540,12 +540,13 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
} }
spin_lock_bh(&ip6_sk_fl_lock); spin_lock_bh(&ip6_sk_fl_lock);
for (sflp = &np->ipv6_fl_list; 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) { sflp = &sfl->next) {
if (sfl->fl->label == freq.flr_label) { if (sfl->fl->label == freq.flr_label) {
if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK)) if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
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); spin_unlock_bh(&ip6_sk_fl_lock);
fl_release(sfl->fl); fl_release(sfl->fl);
kfree_rcu(sfl, rcu); kfree_rcu(sfl, rcu);