+From 50e74d1c748bde8d667e452d4d7cac3d8f869520 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 22 Sep 2016 16:02:37 +0530
+Subject: [PATCH 4/5] net: mcf: limit buffer descriptor count
+
+ColdFire Fast Ethernet Controller uses buffer descriptors to manage
+data flow to/fro receive & transmit queues. While transmitting
+packets, it could continue to read buffer descriptors if a buffer
+descriptor has length of zero and has crafted values in bd.flags.
+Set upper limit to number of buffer descriptors.
+
+Reported-by: Li Qiang <liqiang6-s@360.cn>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+---
+ hw/net/mcf_fec.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/hw/net/mcf_fec.c b/hw/net/mcf_fec.c
+index 7c0398e..6d3418e 100644
+--- a/hw/net/mcf_fec.c
++++ b/hw/net/mcf_fec.c
+@@ -23,6 +23,7 @@ do { printf("mcf_fec: " fmt , ## __VA_ARGS__); } while (0)
+ #define DPRINTF(fmt, ...) do {} while(0)
+ #endif
+
++#define FEC_MAX_DESC 1024
+ #define FEC_MAX_FRAME_SIZE 2032
+
+ typedef struct {
+@@ -149,7 +150,7 @@ static void mcf_fec_do_tx(mcf_fec_state *s)
+ uint32_t addr;
+ mcf_fec_bd bd;
+ int frame_size;
+- int len;
++ int len, descnt = 0;
+ uint8_t frame[FEC_MAX_FRAME_SIZE];
+ uint8_t *ptr;
+
+@@ -157,7 +158,7 @@ static void mcf_fec_do_tx(mcf_fec_state *s)
+ ptr = frame;
+ frame_size = 0;
+ addr = s->tx_descriptor;
+- while (1) {
++ while (descnt++ < FEC_MAX_DESC) {
+ mcf_fec_read_bd(&bd, addr);
+ DPRINTF("tx_bd %x flags %04x len %d data %08x\n",
+ addr, bd.flags, bd.length, bd.data);
+--
+2.1.4
+