diff --git a/SOURCES/bz1765619-1-totemsrp-Reduce-MTU-to-left-room-second-mcast.patch b/SOURCES/bz1765619-1-totemsrp-Reduce-MTU-to-left-room-second-mcast.patch
new file mode 100644
index 0000000..fe5a375
--- /dev/null
+++ b/SOURCES/bz1765619-1-totemsrp-Reduce-MTU-to-left-room-second-mcast.patch
@@ -0,0 +1,45 @@
+From ee8b8993d98b3f6af9c058194228fc534fcd0796 Mon Sep 17 00:00:00 2001
+From: Jan Friesse <jfriesse@redhat.com>
+Date: Mon, 7 Oct 2019 15:26:22 +0200
+Subject: [PATCH] totemsrp: Reduce MTU to left room second mcast
+
+Messages sent during recovery phase are encapsulated so such message has
+extra size of mcast structure. This is not so big problem for UDPU,
+because most of the switches are able to fragment and defragment packet
+but it is problem for knet, because totempg is using maximum packet size
+(65536 bytes) and when another header is added during retransmition,
+then packet is too large.
+
+Solution is to reduce mtu by 2 * sizeof (struct mcast).
+
+Signed-off-by: Jan Friesse <jfriesse@redhat.com>
+Reviewed-by: Fabio M. Di Nitto <fdinitto@redhat.com>
+---
+ exec/totemsrp.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/exec/totemsrp.c b/exec/totemsrp.c
+index 548f1dc..0caded0 100644
+--- a/exec/totemsrp.c
++++ b/exec/totemsrp.c
+@@ -803,7 +803,7 @@ static void totempg_mtu_changed(void *context, int net_mtu)
+ {
+ 	struct totemsrp_instance *instance = context;
+ 
+-	instance->totem_config->net_mtu = net_mtu - sizeof (struct mcast);
++	instance->totem_config->net_mtu = net_mtu - 2 * sizeof (struct mcast);
+ 
+ 	log_printf (instance->totemsrp_log_level_debug,
+ 		    "Net MTU changed to %d, new value is %d",
+@@ -5112,7 +5112,7 @@ void main_iface_change_fn (
+ }
+ 
+ void totemsrp_net_mtu_adjust (struct totem_config *totem_config) {
+-	totem_config->net_mtu -= sizeof (struct mcast);
++	totem_config->net_mtu -= 2 * sizeof (struct mcast);
+ }
+ 
+ void totemsrp_service_ready_register (
+-- 
+1.8.3.1
+
diff --git a/SPECS/corosync.spec b/SPECS/corosync.spec
index c5cb6f6..e7c3dca 100644
--- a/SPECS/corosync.spec
+++ b/SPECS/corosync.spec
@@ -23,10 +23,12 @@
 Name: corosync
 Summary: The Corosync Cluster Engine and Application Programming Interfaces
 Version: 3.0.2
-Release: 3%{?gitver}%{?dist}
+Release: 3%{?gitver}%{?dist}.1
 License: BSD
 URL: http://corosync.github.io/corosync/
 Source0: http://build.clusterlabs.org/corosync/releases/%{name}-%{version}%{?gittarver}.tar.gz
+
+Patch0: bz1765619-1-totemsrp-Reduce-MTU-to-left-room-second-mcast.patch
 %if %{with spausedd}
 Source1: https://github.com/jfriesse/spausedd/releases/download/%{spausedd_version}/spausedd-%{spausedd_version}.tar.gz
 # VMGuestLib exists only for x86_64 architecture
@@ -88,6 +90,8 @@ BuildRequires: pkgconfig(vmguestlib)
 %setup -q -n %{name}-%{version}%{?gittarver}
 %endif
 
+%patch0 -p1 -b .bz1765619-1
+
 %build
 %if %{with runautogen}
 ./autogen.sh
@@ -386,6 +390,12 @@ fi
 %endif
 
 %changelog
+* Wed Oct 30 2019 Jan Friesse <jfriesse@redhat.com> 3.0.2-3.1
+- Resolves: rhbz#1765619
+
+- totemsrp: Reduce MTU to left room second mcast (rhbz#1765619)
+- merge upstream commit ee8b8993d98b3f6af9c058194228fc534fcd0796 (rhbz#1765619)
+
 * Tue Aug 06 2019 Jan Friesse <jfriesse@redhat.com> - 3.0.2-3
 - Resolves: rhbz#1738218