diff --git a/changes/bug31080_041 b/changes/bug31080_041
new file mode 100644
index 0000000000..1fe9ec508d
--- /dev/null
+++ b/changes/bug31080_041
@@ -0,0 +1,4 @@
+  o Minor bugfixes (logging):
+    - Fix a conflict between the flag used for messaging-domain
+      log messages, and the LD_NO_MOCK testing flag. Fixes bug 31080;
+      bugfix on 0.4.1.1-alpha.
diff --git a/src/feature/control/control_events.c b/src/feature/control/control_events.c
index e596a8aee2..9e0966ca54 100644
--- a/src/feature/control/control_events.c
+++ b/src/feature/control/control_events.c
@@ -1287,7 +1287,7 @@ enable_control_logging(void)
 
 /** We got a log message: tell any interested control connections. */
 void
-control_event_logmsg(int severity, uint32_t domain, const char *msg)
+control_event_logmsg(int severity, log_domain_mask_t domain, const char *msg)
 {
   int event;
 
diff --git a/src/feature/control/control_events.h b/src/feature/control/control_events.h
index 0bdbb9cfd2..34986fdb89 100644
--- a/src/feature/control/control_events.h
+++ b/src/feature/control/control_events.h
@@ -128,7 +128,8 @@ int control_event_circ_bandwidth_used_for_circ(origin_circuit_t *ocirc);
 int control_event_conn_bandwidth(connection_t *conn);
 int control_event_conn_bandwidth_used(void);
 int control_event_circuit_cell_stats(void);
-void control_event_logmsg(int severity, uint32_t domain, const char *msg);
+void control_event_logmsg(int severity, log_domain_mask_t domain,
+                          const char *msg);
 void control_event_logmsg_pending(void);
 int control_event_descriptors_changed(smartlist_t *routers);
 int control_event_address_mapped(const char *from, const char *to,
diff --git a/src/lib/defs/include.am b/src/lib/defs/include.am
index dfddc92e55..84ee403771 100644
--- a/src/lib/defs/include.am
+++ b/src/lib/defs/include.am
@@ -3,5 +3,6 @@
 noinst_HEADERS += 			\
 	src/lib/defs/dh_sizes.h 	\
 	src/lib/defs/digest_sizes.h	\
+	src/lib/defs/logging_types.h	\
 	src/lib/defs/time.h      	\
 	src/lib/defs/x25519_sizes.h
diff --git a/src/lib/defs/logging_types.h b/src/lib/defs/logging_types.h
new file mode 100644
index 0000000000..57db818007
--- /dev/null
+++ b/src/lib/defs/logging_types.h
@@ -0,0 +1,23 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file logging_types.h
+ *
+ * \brief Global definition for types used by logging systems.
+ **/
+
+#ifndef TOR_LOGGING_TYPES_H
+#define TOR_LOGGING_TYPES_H
+
+/* We define this here so that it can be used both by backtrace.h and
+ * log.h.
+ */
+
+/** Mask of zero or more log domains, OR'd together. */
+typedef uint64_t log_domain_mask_t;
+
+#endif
diff --git a/src/lib/err/.may_include b/src/lib/err/.may_include
index daa1b6e4ca..314424545e 100644
--- a/src/lib/err/.may_include
+++ b/src/lib/err/.may_include
@@ -1,5 +1,6 @@
 orconfig.h
 lib/cc/*.h
+lib/defs/*.h
 lib/err/*.h
 lib/subsys/*.h
-lib/version/*.h
\ No newline at end of file
+lib/version/*.h
diff --git a/src/lib/err/backtrace.c b/src/lib/err/backtrace.c
index 1d1b3bcfa3..e6cbe3d326 100644
--- a/src/lib/err/backtrace.c
+++ b/src/lib/err/backtrace.c
@@ -115,7 +115,7 @@ clean_backtrace(void **stack, size_t depth, const ucontext_t *ctx)
  * that with a backtrace log.  Send messages via the tor_log function at
  * logger". */
 void
-log_backtrace_impl(int severity, int domain, const char *msg,
+log_backtrace_impl(int severity, log_domain_mask_t domain, const char *msg,
                    tor_log_fn logger)
 {
   size_t depth;
@@ -240,7 +240,7 @@ remove_bt_handler(void)
 
 #ifdef NO_BACKTRACE_IMPL
 void
-log_backtrace_impl(int severity, int domain, const char *msg,
+log_backtrace_impl(int severity, log_domain_mask_t domain, const char *msg,
                    tor_log_fn logger)
 {
   logger(severity, domain, "%s. (Stack trace not available)", msg);
diff --git a/src/lib/err/backtrace.h b/src/lib/err/backtrace.h
index 9b313261e6..dcd22cfef2 100644
--- a/src/lib/err/backtrace.h
+++ b/src/lib/err/backtrace.h
@@ -12,11 +12,14 @@
 
 #include "orconfig.h"
 #include "lib/cc/compat_compiler.h"
+#include "lib/cc/torint.h"
+#include "lib/defs/logging_types.h"
 
-typedef void (*tor_log_fn)(int, unsigned, const char *fmt, ...)
+typedef void (*tor_log_fn)(int, log_domain_mask_t, const char *fmt, ...)
   CHECK_PRINTF(3,4);
 
-void log_backtrace_impl(int severity, int domain, const char *msg,
+void log_backtrace_impl(int severity, log_domain_mask_t domain,
+                        const char *msg,
                         tor_log_fn logger);
 int configure_backtrace_handler(const char *tor_version);
 void clean_up_backtrace_handler(void);
diff --git a/src/lib/log/.may_include b/src/lib/log/.may_include
index 11c87f0a0d..54d96324db 100644
--- a/src/lib/log/.may_include
+++ b/src/lib/log/.may_include
@@ -1,6 +1,7 @@
 orconfig.h
 
 lib/cc/*.h
+lib/defs/*.h
 lib/smartlist_core/*.h
 lib/err/*.h
 lib/fdio/*.h
diff --git a/src/lib/log/log.c b/src/lib/log/log.c
index c68f335da6..d95bf1ff6e 100644
--- a/src/lib/log/log.c
+++ b/src/lib/log/log.c
@@ -1022,7 +1022,7 @@ flush_pending_log_callbacks(void)
   do {
     SMARTLIST_FOREACH_BEGIN(messages, pending_log_message_t *, msg) {
       const int severity = msg->severity;
-      const int domain = msg->domain;
+      const log_domain_mask_t domain = msg->domain;
       for (lf = logfiles; lf; lf = lf->next) {
         if (! lf->callback || lf->seems_dead ||
             ! (lf->severities->masks[SEVERITY_MASK_IDX(severity)] & domain)) {
@@ -1275,6 +1275,8 @@ static const char *domain_list[] = {
 
 CTASSERT(ARRAY_LENGTH(domain_list) == N_LOGGING_DOMAINS + 1);
 
+CTASSERT((UINT64_C(1)<<(N_LOGGING_DOMAINS-1)) < LOWEST_RESERVED_LD_FLAG_);
+
 /** Return a bitmask for the log domain for which <b>domain</b> is the name,
  * or 0 if there is no such name. */
 static log_domain_mask_t
@@ -1375,7 +1377,7 @@ parse_log_severity_config(const char **cfg_ptr,
             if (!strcmp(domain, "*")) {
               domains = ~0u;
             } else {
-              int d;
+              log_domain_mask_t d;
               int negate=0;
               if (*domain == '~') {
                 negate = 1;
diff --git a/src/lib/log/log.h b/src/lib/log/log.h
index 3db2169584..c4a27782c3 100644
--- a/src/lib/log/log.h
+++ b/src/lib/log/log.h
@@ -16,6 +16,7 @@
 #include <stdarg.h>
 #include "lib/cc/torint.h"
 #include "lib/cc/compat_compiler.h"
+#include "lib/defs/logging_types.h"
 #include "lib/testsupport/testsupport.h"
 
 #ifdef HAVE_SYSLOG_H
@@ -56,82 +57,81 @@
 /* Logging domains */
 
 /** Catch-all for miscellaneous events and fatal errors. */
-#define LD_GENERAL  (1u<<0)
+#define LD_GENERAL  (UINT64_C(1)<<0)
 /** The cryptography subsystem. */
-#define LD_CRYPTO   (1u<<1)
+#define LD_CRYPTO   (UINT64_C(1)<<1)
 /** Networking. */
-#define LD_NET      (1u<<2)
+#define LD_NET      (UINT64_C(1)<<2)
 /** Parsing and acting on our configuration. */
-#define LD_CONFIG   (1u<<3)
+#define LD_CONFIG   (UINT64_C(1)<<3)
 /** Reading and writing from the filesystem. */
-#define LD_FS       (1u<<4)
+#define LD_FS       (UINT64_C(1)<<4)
 /** Other servers' (non)compliance with the Tor protocol. */
-#define LD_PROTOCOL (1u<<5)
+#define LD_PROTOCOL (UINT64_C(1)<<5)
 /** Memory management. */
-#define LD_MM       (1u<<6)
+#define LD_MM       (UINT64_C(1)<<6)
 /** HTTP implementation. */
-#define LD_HTTP     (1u<<7)
+#define LD_HTTP     (UINT64_C(1)<<7)
 /** Application (socks) requests. */
-#define LD_APP      (1u<<8)
+#define LD_APP      (UINT64_C(1)<<8)
 /** Communication via the controller protocol. */
-#define LD_CONTROL  (1u<<9)
+#define LD_CONTROL  (UINT64_C(1)<<9)
 /** Building, using, and managing circuits. */
-#define LD_CIRC     (1u<<10)
+#define LD_CIRC     (UINT64_C(1)<<10)
 /** Hidden services. */
-#define LD_REND     (1u<<11)
+#define LD_REND     (UINT64_C(1)<<11)
 /** Internal errors in this Tor process. */
-#define LD_BUG      (1u<<12)
+#define LD_BUG      (UINT64_C(1)<<12)
 /** Learning and using information about Tor servers. */
-#define LD_DIR      (1u<<13)
+#define LD_DIR      (UINT64_C(1)<<13)
 /** Learning and using information about Tor servers. */
-#define LD_DIRSERV  (1u<<14)
+#define LD_DIRSERV  (UINT64_C(1)<<14)
 /** Onion routing protocol. */
-#define LD_OR       (1u<<15)
+#define LD_OR       (UINT64_C(1)<<15)
 /** Generic edge-connection functionality. */
-#define LD_EDGE     (1u<<16)
+#define LD_EDGE     (UINT64_C(1)<<16)
 #define LD_EXIT     LD_EDGE
 /** Bandwidth accounting. */
-#define LD_ACCT     (1u<<17)
+#define LD_ACCT     (UINT64_C(1)<<17)
 /** Router history */
-#define LD_HIST     (1u<<18)
+#define LD_HIST     (UINT64_C(1)<<18)
 /** OR handshaking */
-#define LD_HANDSHAKE (1u<<19)
+#define LD_HANDSHAKE (UINT64_C(1)<<19)
 /** Heartbeat messages */
-#define LD_HEARTBEAT (1u<<20)
+#define LD_HEARTBEAT (UINT64_C(1)<<20)
 /** Abstract channel_t code */
-#define LD_CHANNEL   (1u<<21)
+#define LD_CHANNEL   (UINT64_C(1)<<21)
 /** Scheduler */
-#define LD_SCHED     (1u<<22)
+#define LD_SCHED     (UINT64_C(1)<<22)
 /** Guard nodes */
-#define LD_GUARD     (1u<<23)
+#define LD_GUARD     (UINT64_C(1)<<23)
 /** Generation and application of consensus diffs. */
-#define LD_CONSDIFF  (1u<<24)
+#define LD_CONSDIFF  (UINT64_C(1)<<24)
 /** Denial of Service mitigation. */
-#define LD_DOS       (1u<<25)
+#define LD_DOS       (UINT64_C(1)<<25)
 /** Processes */
-#define LD_PROCESS   (1u<<26)
+#define LD_PROCESS   (UINT64_C(1)<<26)
 /** Pluggable Transports. */
-#define LD_PT        (1u<<27)
+#define LD_PT        (UINT64_C(1)<<27)
 /** Bootstrap tracker. */
-#define LD_BTRACK    (1u<<28)
+#define LD_BTRACK    (UINT64_C(1)<<28)
 /** Message-passing backend. */
-#define LD_MESG      (1u<<29)
+#define LD_MESG      (UINT64_C(1)<<29)
 #define N_LOGGING_DOMAINS 30
 
+/** First bit that is reserved in log_domain_mask_t for non-domain flags. */
+#define LOWEST_RESERVED_LD_FLAG_ (UINT64_C(1)<<61)
+#ifdef TOR_UNIT_TESTS
+/** This log message should not be intercepted by mock_saving_logv */
+#define LD_NO_MOCK (UINT64_C(1)<<61)
+#endif
+
 /** This log message is not safe to send to a callback-based logger
  * immediately.  Used as a flag, not a log domain. */
-#define LD_NOCB (1u<<31)
+#define LD_NOCB (UINT64_C(1)<<62)
 /** This log message should not include a function name, even if it otherwise
  * would. Used as a flag, not a log domain. */
-#define LD_NOFUNCNAME (1u<<30)
-
-#ifdef TOR_UNIT_TESTS
-/** This log message should not be intercepted by mock_saving_logv */
-#define LD_NO_MOCK (1u<<29)
-#endif
-
-/** Mask of zero or more log domains, OR'd together. */
-typedef uint32_t log_domain_mask_t;
+#define LD_NOFUNCNAME (UINT64_C(1)<<63)
 
 /** Configures which severities are logged for each logging domain for a given
  * log target. */
@@ -142,7 +142,8 @@ typedef struct log_severity_list_t {
 } log_severity_list_t;
 
 /** Callback type used for add_callback_log. */
-typedef void (*log_callback)(int severity, uint32_t domain, const char *msg);
+typedef void (*log_callback)(int severity, log_domain_mask_t domain,
+                             const char *msg);
 
 void init_logging(int disable_startup_queue);
 int parse_log_level(const char *level);
diff --git a/src/rust/tor_log/tor_log.rs b/src/rust/tor_log/tor_log.rs
index 98fccba5a9..bbaf97129c 100644
--- a/src/rust/tor_log/tor_log.rs
+++ b/src/rust/tor_log/tor_log.rs
@@ -99,14 +99,14 @@ pub mod log {
     /// Domain log types. These mirror definitions in src/lib/log/log.h
     /// C_RUST_COUPLED: src/lib/log/log.c, log severity types
     extern "C" {
-        static LD_NET_: u32;
-        static LD_GENERAL_: u32;
+        static LD_NET_: u64;
+        static LD_GENERAL_: u64;
     }
 
     /// Translate Rust defintions of log domain levels to C. This exposes a 1:1
     /// mapping between types.
     #[inline]
-    pub unsafe fn translate_domain(domain: LogDomain) -> u32 {
+    pub unsafe fn translate_domain(domain: LogDomain) -> u64 {
         match domain {
             LogDomain::Net => LD_NET_,
             LogDomain::General => LD_GENERAL_,
@@ -128,7 +128,7 @@ pub mod log {
     extern "C" {
         pub fn tor_log_string(
             severity: c_int,
-            domain: u32,
+            domain: u64,
             function: *const c_char,
             string: *const c_char,
         );
diff --git a/src/test/test_logging.c b/src/test/test_logging.c
index 6416e98a4e..bb7018fe1c 100644
--- a/src/test/test_logging.c
+++ b/src/test/test_logging.c
@@ -15,7 +15,7 @@
 #endif
 
 static void
-dummy_cb_fn(int severity, uint32_t domain, const char *msg)
+dummy_cb_fn(int severity, log_domain_mask_t domain, const char *msg)
 {
   (void)severity; (void)domain; (void)msg;
 }
diff --git a/src/test/test_options.c b/src/test/test_options.c
index b39cd4f1e4..64fcd011e7 100644
--- a/src/test/test_options.c
+++ b/src/test/test_options.c
@@ -31,14 +31,14 @@
 
 typedef struct {
   int severity;
-  uint32_t domain;
+  log_domain_mask_t domain;
   char *msg;
 } logmsg_t;
 
 static smartlist_t *messages = NULL;
 
 static void
-log_cback(int severity, uint32_t domain, const char *msg)
+log_cback(int severity, log_domain_mask_t domain, const char *msg)
 {
   logmsg_t *x = tor_malloc(sizeof(*x));
   x->severity = severity;
diff --git a/src/test/testing_common.c b/src/test/testing_common.c
index 1c2a2e8960..ad22898ce5 100644
--- a/src/test/testing_common.c
+++ b/src/test/testing_common.c
@@ -243,7 +243,7 @@ tinytest_postfork(void)
 }
 
 static void
-log_callback_failure(int severity, uint32_t domain, const char *msg)
+log_callback_failure(int severity, log_domain_mask_t domain, const char *msg)
 {
   (void)msg;
   if (severity == LOG_ERR || (domain & LD_BUG)) {