From: Jason Wang <jasowang@redhat.com>
Date: Fri, 9 Mar 2018 14:50:34 +0800
Subject: vhost_net: examine pointer types during un-producing
Patch-mainline: v4.16-rc7
Git-commit: 3a4030761ea88ff439030ca98e3094b9900e96b7
References: bsc#1109837

After commit fc72d1d54dd9 ("tuntap: XDP transmission"), we can
actually queueing XDP pointers in the pointer ring, so we should
examine the pointer type before freeing the pointer.

Fixes: fc72d1d54dd9 ("tuntap: XDP transmission")
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/tun.c      |    3 ++-
 drivers/vhost/net.c    |    2 +-
 include/linux/if_tun.h |    4 ++++
 3 files changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -655,7 +655,7 @@ static struct tun_struct *tun_enable_que
 	return tun;
 }
 
-static void tun_ptr_free(void *ptr)
+void tun_ptr_free(void *ptr)
 {
 	if (!ptr)
 		return;
@@ -667,6 +667,7 @@ static void tun_ptr_free(void *ptr)
 		__skb_array_destroy_skb(ptr);
 	}
 }
+EXPORT_SYMBOL_GPL(tun_ptr_free);
 
 static void tun_queue_purge(struct tun_file *tfile)
 {
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -170,7 +170,7 @@ static void vhost_net_buf_unproduce(stru
 	if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
 		ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head,
 				   vhost_net_buf_get_size(rxq),
-				   __skb_array_destroy_skb);
+				   tun_ptr_free);
 		rxq->head = rxq->tail = 0;
 	}
 }
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -25,6 +25,7 @@ struct ptr_ring *tun_get_tx_ring(struct
 bool tun_is_xdp_buff(void *ptr);
 void *tun_xdp_to_ptr(void *ptr);
 void *tun_ptr_to_xdp(void *ptr);
+void tun_ptr_free(void *ptr);
 #else
 #include <linux/err.h>
 #include <linux/errno.h>
@@ -50,5 +51,8 @@ void *tun_ptr_to_xdp(void *ptr)
 {
 	return NULL;
 }
+static inline void tun_ptr_free(void *ptr)
+{
+}
 #endif /* CONFIG_TUN */
 #endif /* __IF_TUN_H */