From c95039410e989f180e918e635c938b70dd9e479e Mon Sep 17 00:00:00 2001
From: Coiby Xu <coxu@redhat.com>
Date: Tue, 16 May 2023 14:43:41 +0800
Subject: [PATCH] Don't rename Azure Hyper-V network interface

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1964822
Upstream: RHEL-only

Currently, vmcore dumping to remote fs gives a warning "eth0: Failed to
rename network interface 3 from 'eth0' to 'kdump-eth0': File exists" on
Azure Hyper-V VM with accelerated networking because it uses a physical
NIC for accelerated networking [1] and the backing physical NIC has the
same MAC as the virtual NIC. There is no need to rename a Hypver-V
interface in this case which also leads the aforementioned warning.

[1] https://learn.microsoft.com/en-us/azure/virtual-network/accelerated-networking-overview

Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 dracut-module-setup.sh | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 9cbb5d6..e250703 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -303,6 +303,10 @@ kdump_get_perm_addr() {
     fi
 }
 
+_get_nic_driver() {
+    ethtool -i "$1" | sed -n -E "s/driver: (.*)/\1/p"
+}
+
 # Prefix kernel assigned names with "kdump-". EX: eth0 -> kdump-eth0
 # Because kernel assigned names are not persistent between 1st and 2nd
 # kernel. We could probably end up with eth0 being eth1, eth0 being
@@ -314,7 +318,7 @@ kdump_setup_ifname() {
     # fadump to kdump. Skip prefixing 'kdump-' in this case as adding
     # another prefix may truncate the ifname. Since an ifname with
     # 'kdump-' is already persistent, this should be fine.
-    if [[ $1 =~ eth* ]] && [[ ! $1 =~ ^kdump-* ]]; then
+    if [[ $1 =~ eth* ]] && [[ ! $1 =~ ^kdump-* ]] && [[ $(_get_nic_driver "$1") != hv_netvsc ]]; then
         _ifname="kdump-$1"
     else
         _ifname="$1"