From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 65a3c497c0e965a552008db8bc2653f62bc925a1 ]
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@xxxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -254,9 +254,9 @@ struct ip6_flowlabel *fl6_sock_lookup(st
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;
}
@@ -622,7 +622,8 @@ 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;
}
}
