[ Upstream commit 0cd6783d3c7d40be165d1f3c811cedf0e3dfcdf1 ]
While qeth_l3 uses netif_keep_dst() to hold onto the dst, a skb's dst may still have been obsoleted (via dst_dev_put()) by the time that we end up using it. The dst then points to the loopback interface, which means the neighbour lookup in qeth_l3_get_cast_type() determines a bogus cast type of RTN_BROADCAST. For IQD interfaces this causes us to place such skbs on the wrong HW queue, resulting in TX errors.
Fix-up the various call sites to first validate the dst entry with dst_check(), and fall back accordingly.
Signed-off-by: Julian Wiedmann jwi@linux.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/net/qeth_l3_main.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index cb641fd303d3..93a5748036de 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -1883,13 +1883,20 @@ static int qeth_l3_do_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
static int qeth_l3_get_cast_type(struct sk_buff *skb) { + int ipv = qeth_get_ip_version(skb); struct neighbour *n = NULL; struct dst_entry *dst;
rcu_read_lock(); dst = skb_dst(skb); - if (dst) - n = dst_neigh_lookup_skb(dst, skb); + if (dst) { + struct rt6_info *rt = (struct rt6_info *) dst; + + dst = dst_check(dst, (ipv == 6) ? rt6_get_cookie(rt) : 0); + if (dst) + n = dst_neigh_lookup_skb(dst, skb); + } + if (n) { int cast_type = n->type;
@@ -1904,7 +1911,7 @@ static int qeth_l3_get_cast_type(struct sk_buff *skb) rcu_read_unlock();
/* no neighbour (eg AF_PACKET), fall back to target's IP address ... */ - switch (qeth_get_ip_version(skb)) { + switch (ipv) { case 4: if (ipv4_is_lbcast(ip_hdr(skb)->daddr)) return RTN_BROADCAST; @@ -1943,6 +1950,7 @@ static void qeth_l3_fill_header(struct qeth_qdio_out_q *queue, struct qeth_hdr_layer3 *l3_hdr = &hdr->hdr.l3; struct vlan_ethhdr *veth = vlan_eth_hdr(skb); struct qeth_card *card = queue->card; + struct dst_entry *dst;
hdr->hdr.l3.length = data_len;
@@ -1993,15 +2001,27 @@ static void qeth_l3_fill_header(struct qeth_qdio_out_q *queue,
hdr->hdr.l3.flags = qeth_l3_cast_type_to_flag(cast_type); rcu_read_lock(); + dst = skb_dst(skb); + if (ipv == 4) { - struct rtable *rt = skb_rtable(skb); + struct rtable *rt; + + if (dst) + dst = dst_check(dst, 0); + rt = (struct rtable *) dst;
*((__be32 *) &hdr->hdr.l3.next_hop.ipv4.addr) = (rt) ? rt_nexthop(rt, ip_hdr(skb)->daddr) : ip_hdr(skb)->daddr; } else { /* IPv6 */ - const struct rt6_info *rt = skb_rt6_info(skb); + struct rt6_info *rt; + + if (dst) { + rt = (struct rt6_info *) dst; + dst = dst_check(dst, rt6_get_cookie(rt)); + } + rt = (struct rt6_info *) dst;
if (rt && !ipv6_addr_any(&rt->rt6i_gateway)) l3_hdr->next_hop.ipv6_addr = rt->rt6i_gateway;