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authorEric Dumazet <edumazet@google.com>2017-05-11 15:24:41 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-07 12:05:59 +0200
commit605b6b2b4d8a8abdafb675abda2e43c11d1b3921 (patch)
tree57cb55fbbf7486c6526a81ea118f3d35812d584c /net
parent338f665acb4ba0b2c7656cc2487326497220168f (diff)
netem: fix skb_orphan_partial()
commit f6ba8d33cfbb46df569972e64dbb5bb7e929bfd9 upstream. I should have known that lowering skb->truesize was dangerous :/ In case packets are not leaving the host via a standard Ethernet device, but looped back to local sockets, bad things can happen, as reported by Michael Madsen ( https://bugzilla.kernel.org/show_bug.cgi?id=195713 ) So instead of tweaking skb->truesize, lets change skb->destructor and keep a reference on the owner socket via its sk_refcnt. Fixes: f2f872f9272a ("netem: Introduce skb_orphan_partial() helper") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Michael Madsen <mkm@nabto.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/sock.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 9c708a5fb751..bd2fad27891e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1690,17 +1690,17 @@ EXPORT_SYMBOL(skb_set_owner_w);
void skb_orphan_partial(struct sk_buff *skb)
{
- /* TCP stack sets skb->ooo_okay based on sk_wmem_alloc,
- * so we do not completely orphan skb, but transfert all
- * accounted bytes but one, to avoid unexpected reorders.
- */
if (skb->destructor == sock_wfree
#ifdef CONFIG_INET
|| skb->destructor == tcp_wfree
#endif
) {
- atomic_sub(skb->truesize - 1, &skb->sk->sk_wmem_alloc);
- skb->truesize = 1;
+ struct sock *sk = skb->sk;
+
+ if (atomic_inc_not_zero(&sk->sk_refcnt)) {
+ atomic_sub(skb->truesize, &sk->sk_wmem_alloc);
+ skb->destructor = sock_efree;
+ }
} else {
skb_orphan(skb);
}