diff --git a/cmdline/mingw.c b/cmdline/mingw.c
index 3fd50962..07c617c1 100644
--- a/cmdline/mingw.c
+++ b/cmdline/mingw.c
@@ -1834,21 +1834,6 @@ int randomize(void* ptr, size_t size)
 	return 0;
 }
 
-/**
- * Mutex used for printf.
- *
- * In Windows printf() is not atomic, and multiple threads
- * will have output interleaved.
- *
- * Note that even defining __USE_MINGW_ANSI_STDIO the problem persists.
- *
- * See for example:
- *
- * Weird output when I use pthread and printf.
- * http://stackoverflow.com/questions/13190254/weird-output-when-i-use-pthread-and-printf
- */
-static pthread_mutex_t io_lock = PTHREAD_MUTEX_INITIALIZER;
-
 /**
  * Get the device file from a path inside the device.
  */
@@ -2044,9 +2029,7 @@ static int devscan(tommy_list* list)
 	f = _wpopen(cmd, L"rt");
 	if (!f) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' (from popen).\n", u16tou8(cmd));
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2061,17 +2044,13 @@ static int devscan(tommy_list* list)
 	ret = pclose(f);
 	if (ret == -1) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' (from pclose).\n", u16tou8(cmd));
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
 	if (ret != 0) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' with return code %xh.\n", u16tou8(cmd), ret);
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2106,16 +2085,12 @@ static int devsmart(uint64_t device, const char* name, const char* custom, uint6
 	count = 0;
 
 retry:
-	pthread_mutex_lock(&io_lock);
 	msg_tag("smartctl:run:%s: %s\n", name, u16tou8(cmd));
-	pthread_mutex_unlock(&io_lock);
 
 	f = _wpopen(cmd, L"rt");
 	if (!f) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' (from popen).\n", u16tou8(cmd));
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2129,15 +2104,11 @@ retry:
 
 	ret = pclose(f);
 
-	pthread_mutex_lock(&io_lock);
 	msg_tag("smartctl:ret:%s: 0x%x\n", name, ret);
-	pthread_mutex_unlock(&io_lock);
 
 	if (ret == -1) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' (from pclose).\n", u16tou8(cmd));
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2198,21 +2169,15 @@ static int devdown(uint64_t device, const char* name, const char* custom)
 	count = 0;
 
 retry:
-	pthread_mutex_lock(&io_lock);
 	msg_tag("smartctl:run:%s: %s\n", name, u16tou8(cmd));
-	pthread_mutex_unlock(&io_lock);
 
 	ret = _wsystem(cmd);
 
-	pthread_mutex_lock(&io_lock);
 	msg_tag("smartctl:ret:%s: 0x%x\n", name, ret);
-	pthread_mutex_unlock(&io_lock);
 
 	if (ret == -1) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' (from system).\n", u16tou8(cmd));
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2238,9 +2203,7 @@ retry:
 
 	if (ret != 0) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to run '%s' with return code %xh.\n", u16tou8(cmd), ret);
-		pthread_mutex_unlock(&io_lock);
 		return -1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2289,9 +2252,7 @@ static void* thread_spinup(void* arg)
 	/* we cannot use FindFirstFile because it doesn't allow to open the root dir */
 	if (lstat_sync(devinfo->mount, &st, 0) != 0) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to stat path '%s'. %s.\n", devinfo->mount, strerror(errno));
-		pthread_mutex_unlock(&io_lock);
 		return (void*)-1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2301,9 +2262,7 @@ static void* thread_spinup(void* arg)
 
 	if (devresolve(devinfo->mount, devinfo->file, sizeof(devinfo->file), devinfo->wfile, sizeof(devinfo->wfile)) != 0) {
 		/* LCOV_EXCL_START */
-		pthread_mutex_lock(&io_lock);
 		msg_error("Failed to resolve path '%s'.\n", devinfo->mount);
-		pthread_mutex_unlock(&io_lock);
 		return (void*)-1;
 		/* LCOV_EXCL_STOP */
 	}
@@ -2314,9 +2273,7 @@ static void* thread_spinup(void* arg)
 		/* LCOV_EXCL_STOP */
 	}
 
-	pthread_mutex_lock(&io_lock);
 	msg_status("Spunup device '%s' for disk '%s' in %" PRIu64 " ms.\n", devinfo->file, devinfo->name, tick_ms() - start);
-	pthread_mutex_unlock(&io_lock);
 
 	return 0;
 }
@@ -2337,9 +2294,7 @@ static void* thread_spindown(void* arg)
 		/* LCOV_EXCL_STOP */
 	}
 
-	pthread_mutex_lock(&io_lock);
 	msg_status("Spundown device '%s' for disk '%s' in %" PRIu64 " ms.\n", devinfo->file, devinfo->name, tick_ms() - start);
-	pthread_mutex_unlock(&io_lock);
 
 	return 0;
 }
diff --git a/cmdline/support.c b/cmdline/support.c
index fa0b6324..f9550741 100644
--- a/cmdline/support.c
+++ b/cmdline/support.c
@@ -24,6 +24,24 @@
 
 int msg_level = 0;
 
+/**
+ * Mutex used for printf.
+ *
+ * In Windows printf() is not atomic, and multiple threads
+ * will have output interleaved.
+ *
+ * Note that even defining __USE_MINGW_ANSI_STDIO the problem persists.
+ *
+ * See for example:
+ *
+ * Weird output when I use pthread and printf.
+ * http://stackoverflow.com/questions/13190254/weird-output-when-i-use-pthread-and-printf
+ *
+ * This is also required in other OS because we split output in stdlog in
+ * two fprintf calls.
+ */
+static pthread_mutex_t msg_lock = PTHREAD_MUTEX_INITIALIZER;
+
 /*
  * Note that in the following functions we always flush both
  * stdout and stderr, because we want to ensure that they mixes
@@ -40,6 +58,8 @@ void msg_error(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog) {
 		va_start(ap, format);
 		fprintf(stdlog, "msg:error: ");
@@ -52,12 +72,16 @@ void msg_error(const char* format, ...)
 	vfprintf(stderr, format, ap);
 	fflush(stderr);
 	va_end(ap);
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_warning(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog) {
 		va_start(ap, format);
 		fprintf(stdlog, "msg:warning: ");
@@ -70,6 +94,8 @@ void msg_warning(const char* format, ...)
 		fflush(stderr);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_tag(const char* format, ...)
@@ -87,6 +113,8 @@ void msg_status(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog) {
 		va_start(ap, format);
 		fprintf(stdlog, "msg:status: ");
@@ -101,12 +129,16 @@ void msg_status(const char* format, ...)
 		fflush(stdout);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_info(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	/* don't output in stdlog as these messages */
 	/* are always paired with a msg_tag() call */
 
@@ -116,12 +148,16 @@ void msg_info(const char* format, ...)
 		fflush(stdout);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_progress(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog) {
 		va_start(ap, format);
 		fprintf(stdlog, "msg:progress: ");
@@ -136,12 +172,16 @@ void msg_progress(const char* format, ...)
 		fflush(stdout);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_bar(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	/* don't output in stdlog as these messages */
 	/* are intended for screen only */
 	/* also don't flush stdout as they are intended to be partial messages */
@@ -151,12 +191,16 @@ void msg_bar(const char* format, ...)
 		vfprintf(stdout, format, ap);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_verbose(const char* format, ...)
 {
 	va_list ap;
 
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog) {
 		va_start(ap, format);
 		fprintf(stdlog, "msg:verbose: ");
@@ -171,14 +215,20 @@ void msg_verbose(const char* format, ...)
 		fflush(stdout);
 		va_end(ap);
 	}
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 void msg_flush(void)
 {
+	pthread_mutex_lock(&msg_lock);
+
 	if (stdlog)
 		fflush(stdlog);
 	fflush(stdout);
 	fflush(stderr);
+
+	pthread_mutex_unlock(&msg_lock);
 }
 
 /**