From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 21 Oct 2016 17:39:29 +0530
Subject: [PATCH] net: rtl8139: limit processing of ring descriptors

RTL8139 ethernet controller in C+ mode supports multiple
descriptor rings, each with maximum of 64 descriptors. While
processing transmit descriptor ring in 'rtl8139_cplus_transmit',
it does not limit the descriptor count and runs forever. Add
check to avoid it.

Reported-by: Andrew Henderson <hendersa@icculus.org>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit c7c35916692fe010fef25ac338443d3fe40be225)
---
 hw/net/rtl8139.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 1e5ec14..138fa62 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2379,7 +2379,7 @@ static void rtl8139_cplus_transmit(RTL8139State *s)
 {
     int txcount = 0;
 
-    while (rtl8139_cplus_transmit_one(s))
+    while (txcount < 64 && rtl8139_cplus_transmit_one(s))
     {
         ++txcount;
     }