diff -Nru systemd-237/debian/changelog systemd-237/debian/changelog
--- systemd-237/debian/changelog	2019-08-29 22:30:33.000000000 +0000
+++ systemd-237/debian/changelog	2019-09-05 03:59:51.000000000 +0000
@@ -1,3 +1,12 @@
+systemd (237-3ubuntu10.29) bionic; urgency=medium
+
+  * d/p/d/Revert-udev-network-device-renaming-immediately-give.patch:
+    - udev: add Revert-udev-network-device-renaming-immediately-give.patch back
+      Dropping this patch will cause the persistent network regression.
+      (LP: #1842651)
+
+ -- Shih-Yuan Lee (FourDollars) <sylee@canonical.com>  Thu, 05 Sep 2019 11:59:51 +0800
+
 systemd (237-3ubuntu10.28) bionic-security; urgency=medium
 
   * SECURITY UPDATE: Unprivileged users are granted access to privileged
diff -Nru systemd-237/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch systemd-237/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch
--- systemd-237/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch	1970-01-01 00:00:00.000000000 +0000
+++ systemd-237/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch	2019-09-05 03:59:51.000000000 +0000
@@ -0,0 +1,75 @@
+From: Michael Biebl <biebl@debian.org>
+Date: Thu, 18 Jul 2013 01:04:07 +0200
+Subject: Revert "udev: network device renaming - immediately give up if the
+ target name isn't available"
+
+This reverts commit 97595710b77aa162ca5e20da57d0a1ed7355eaad.
+
+We need to keep supporting systems with 75-persistent-net-generator.rules
+generated names for a while after switching to net.ifnames. Re-apply this old
+hack to make the renaming less likely to fail.
+---
+ src/udev/udev-event.c | 41 ++++++++++++++++++++++++++++++++++++++---
+ 1 file changed, 38 insertions(+), 3 deletions(-)
+
+diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
+index d0befba..c3ed2da 100644
+--- a/src/udev/udev-event.c
++++ b/src/udev/udev-event.c
+@@ -832,18 +832,53 @@ static int rename_netif(struct udev_event *event) {
+         char name[IFNAMSIZ];
+         const char *oldname;
+         int r;
++        int loop;
+ 
+         oldname = udev_device_get_sysname(dev);
+ 
+         strscpy(name, IFNAMSIZ, event->name);
+ 
++        r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
++        if (r >= 0) {
++                log_debug("renamed network interface %s to %s\n", oldname, name);
++                goto out;
++        }
++
++        /* keep trying if the destination interface name already exists */
++        if (r != -EEXIST)
++                goto out;
++
++        /* free our own name, another process may wait for us */
++        snprintf(name, IFNAMSIZ, "rename%u", udev_device_get_ifindex(dev));
+         r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
+         if (r < 0)
+-                return log_error_errno(r, "Error changing net interface name '%s' to '%s': %m", oldname, name);
++                  goto out;
+ 
+-        log_debug("renamed network interface '%s' to '%s'", oldname, name);
++        /* log temporary name */
++        log_debug("renamed network interface %s to %s\n", oldname, name);
+ 
+-        return 0;
++        /* wait a maximum of 90 seconds for our target to become available */
++        strscpy(name, IFNAMSIZ, event->name);
++        loop = 90 * 20;
++        while (loop--) {
++                const struct timespec duration = { 0, 1000 * 1000 * 1000 / 20 };
++
++                nanosleep(&duration, NULL);
++
++                r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
++                if (r >= 0) {
++                        log_debug("renamed network interface %s to %s\n", oldname, name);
++                        break;
++                }
++                if (r != -EEXIST)
++                        break;
++        }
++
++out:
++        if (r < 0)
++                log_error("error changing net interface name '%s' to '%s': %s",
++                          oldname, name, strerror(-r));
++        return r;
+ }
+ 
+ void udev_event_execute_rules(struct udev_event *event,
diff -Nru systemd-237/debian/patches/series systemd-237/debian/patches/series
--- systemd-237/debian/patches/series	2019-08-29 22:30:33.000000000 +0000
+++ systemd-237/debian/patches/series	2019-09-05 03:59:51.000000000 +0000
@@ -42,6 +42,7 @@
 debian/Add-note-to-udev.conf-that-changes-to-that-file-requ.patch
 debian/Bring-tmpfiles.d-tmp.conf-in-line-with-Debian-defaul.patch
 debian/Make-run-lock-tmpfs-an-API-fs.patch
+debian/Revert-udev-network-device-renaming-immediately-give.patch
 debian/Add-support-for-TuxOnIce-hibernation.patch
 debian/Include-additional-directories-in-ProtectSystem.patch
 debian/Re-enable-journal-forwarding-to-syslog.patch