netdev - [net-next PATCH 09/14] net: sched: check for frozen queue before skb_bad

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20171207175641.5771.42808.stgit@john-Precision-Tower-5810>
Date:   Thu, 07 Dec 2017 09:56:42 -0800
From:   John Fastabend <john.fastabend@...il.com>
To:     willemdebruijn.kernel@...il.com, daniel@...earbox.net,
        eric.dumazet@...il.com, davem@...emloft.net
Cc:     netdev@...r.kernel.org, jiri@...nulli.us, xiyou.wangcong@...il.com
Subject: [net-next PATCH 09/14] net: sched: check for frozen queue before
 skb_bad_txq check

I can not think of any reason to pull the bad txq skb off the qdisc if
the txq we plan to send this on is still frozen. So check for frozen
queue first and abort before dequeuing either skb_bad_txq skb or
normal qdisc dequeue() skb.

Signed-off-by: John Fastabend <john.fastabend@...il.com>
---
 net/sched/sch_generic.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 84cef05..5ff93c2 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -204,7 +204,7 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 				   int *packets)
 {
 	const struct netdev_queue *txq = q->dev_queue;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 
 	*packets = 1;
 	if (unlikely(!skb_queue_empty(&q->gso_skb))) {
@@ -248,12 +248,15 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 	}
 validate:
 	*validate = true;
+
+	if ((q->flags & TCQ_F_ONETXQUEUE) &&
+	    netif_xmit_frozen_or_stopped(txq))
+		return skb;
+
 	skb = qdisc_dequeue_skb_bad_txq(q);
 	if (unlikely(skb))
 		goto bulk;
-	if (!(q->flags & TCQ_F_ONETXQUEUE) ||
-	    !netif_xmit_frozen_or_stopped(txq))
-		skb = q->dequeue(q);
+	skb = q->dequeue(q);
 	if (skb) {
 bulk:
 		if (qdisc_may_bulk(q))