From: Eric Dumazet <edumazet@google.com>
Date: Tue, 28 Jun 2016 08:30:08 +0000 (+0200)
Subject: net_sched: netem: do not call qdisc_drop() with a NULL skb
X-Git-Tag: v4.8-rc1~140^2~233
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=8a6e9c670341db1ee913e3888cb44a08f18e7489;p=uclinux-h8%2Flinux.git

net_sched: netem: do not call qdisc_drop() with a NULL skb

If skb_unshare() fails, we call qdisc_drop() with a NULL skb, which
is no longer supported.

Fixes: 520ac30f4551 ("net_sched: drop packets after root qdisc lock is released")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index ccca8ca4c722..6eac3d880048 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -487,10 +487,14 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		skb = segs;
 		segs = segs->next;
 
-		if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
-		    (skb->ip_summed == CHECKSUM_PARTIAL &&
-		     skb_checksum_help(skb))) {
-			rc = qdisc_drop(skb, sch, to_free);
+		skb = skb_unshare(skb, GFP_ATOMIC);
+		if (unlikely(!skb)) {
+			qdisc_qstats_drop(sch);
+			goto finish_segs;
+		}
+		if (skb->ip_summed == CHECKSUM_PARTIAL &&
+		    skb_checksum_help(skb)) {
+			qdisc_drop(skb, sch, to_free);
 			goto finish_segs;
 		}