3.16.75-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 65a3c497c0e965a552008db8bc2653f62bc925a1 upstream.
Before taking a refcount, make sure the object is not already scheduled for deletion.
Same fix is needed in ipv6_flowlabel_opt()
Fixes: 18367681a10b ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/ipv6/ip6_flowlabel.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -255,9 +255,9 @@ struct ip6_flowlabel * fl6_sock_lookup(s rcu_read_lock_bh(); for_each_sk_fl_rcu(np, sfl) { struct ip6_flowlabel *fl = sfl->fl; - if (fl->label == label) { + + if (fl->label == label && atomic_inc_not_zero(&fl->users)) { fl->lastuse = jiffies; - atomic_inc(&fl->users); rcu_read_unlock_bh(); return fl; } @@ -619,7 +619,8 @@ int ipv6_flowlabel_opt(struct sock *sk, goto done; } fl1 = sfl->fl; - atomic_inc(&fl1->users); + if (!atomic_inc_not_zero(&fl1->users)) + fl1 = NULL; break; } }