diff --git a/Makefile.am b/Makefile.am
index d565978266..c29660ce07 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -3913,7 +3913,8 @@ gperf_gperf_sources += \
 libudev_core_la_CFLAGS = \
 	$(AM_CFLAGS) \
 	$(BLKID_CFLAGS) \
-	$(KMOD_CFLAGS)
+	$(KMOD_CFLAGS) \
+	-DLOG_REALM=LOG_REALM_UDEV
 
 libudev_core_la_LIBADD = \
 	libsystemd-network.la \
@@ -3945,6 +3946,10 @@ endif
 systemd_udevd_SOURCES = \
 	src/udev/udevd.c
 
+systemd_udevd_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 systemd_udevd_LDADD = \
 	libudev-core.la \
 	libbasic.la
@@ -4088,6 +4093,10 @@ EXTRA_DIST += \
 ata_id_SOURCES = \
 	src/udev/ata_id/ata_id.c
 
+ata_id_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 ata_id_LDADD = \
 	libshared.la
 
@@ -4098,6 +4107,10 @@ udevlibexec_PROGRAMS += \
 cdrom_id_SOURCES = \
 	src/udev/cdrom_id/cdrom_id.c
 
+cdrom_id_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 cdrom_id_LDADD = \
 	libshared.la
 
@@ -4111,6 +4124,10 @@ dist_udevrules_DATA += \
 collect_SOURCES = \
 	src/udev/collect/collect.c
 
+collect_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 collect_LDADD = \
 	libshared.la
 
@@ -4124,6 +4141,10 @@ scsi_id_SOURCES =\
 	src/udev/scsi_id/scsi.h \
 	src/udev/scsi_id/scsi_id.h
 
+scsi_id_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 scsi_id_LDADD = \
 	libshared.la
 
@@ -4137,6 +4158,10 @@ EXTRA_DIST += \
 v4l_id_SOURCES = \
 	src/udev/v4l_id/v4l_id.c
 
+v4l_id_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 v4l_id_LDADD = \
 	libshared.la
 
@@ -4152,6 +4177,10 @@ mtd_probe_SOURCES =  \
 	src/udev/mtd_probe/mtd_probe.h \
 	src/udev/mtd_probe/probe_smartmedia.c
 
+mtd_probe_CFLAGS = \
+	$(AM_CFLAGS) \
+       -DLOG_REALM=LOG_REALM_UDEV
+
 dist_udevrules_DATA += \
 	rules/75-probe_mtd.rules
 
diff --git a/meson.build b/meson.build
index 14a20530d4..6d62ec7fab 100644
--- a/meson.build
+++ b/meson.build
@@ -2055,6 +2055,7 @@ public_programs += [exe]
 exe = executable('systemd-udevd',
                  systemd_udevd_sources,
                  include_directories : includes,
+                 c_args : ['-DLOG_REALM=LOG_REALM_UDEV'],
                  link_with : [libudev_core,
                               libsystemd_network,
                               libudev_internal],
diff --git a/src/udev/meson.build b/src/udev/meson.build
index 9692ddc1e9..9067de97dc 100644
--- a/src/udev/meson.build
+++ b/src/udev/meson.build
@@ -130,6 +130,7 @@ foreach prog : [['ata_id/ata_id.c'],
         executable(prog[0].split('/')[0],
                    prog,
                    include_directories : includes,
+                   c_args : ['-DLOG_REALM=LOG_REALM_UDEV'],
                    link_with : [libudev_internal],
                    install_rpath : udev_rpath,
                    install : true,