diff --git a/src/add-ons/kernel/drivers/ports/pc_serial/Tracing.cpp b/src/add-ons/kernel/drivers/ports/pc_serial/Tracing.cpp
index 2ed74ff85b..1c005a7596 100644
--- a/src/add-ons/kernel/drivers/ports/pc_serial/Tracing.cpp
+++ b/src/add-ons/kernel/drivers/ports/pc_serial/Tracing.cpp
@@ -95,7 +95,7 @@ pc_serial_trace(bool force, const char *format, ...)
 		close(fd);
 		release_sem(sLogLock);
 	} else
-		dprintf(buffer);
+		dprintf("%s", buffer);
 }
 
 
diff --git a/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp b/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
index ac8488cf1d..be3b3684fb 100644
--- a/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
+++ b/src/add-ons/kernel/drivers/ports/usb_serial/Tracing.cpp
@@ -98,7 +98,7 @@ usb_serial_trace(bool force, const char *format, ...)
 		close(fd);
 		release_sem(sLogLock);
 	} else
-		dprintf(buffer);
+		dprintf("%s", buffer);
 }