diff --git a/src/os/unix/crashlog_unix.cpp b/src/os/unix/crashlog_unix.cpp
--- a/src/os/unix/crashlog_unix.cpp
+++ b/src/os/unix/crashlog_unix.cpp
@@ -40,7 +40,7 @@ class CrashLogUnix : public CrashLog {
 	/** Signal that has been thrown. */
 	int signum;
 
-	/* virtual */ char *LogOSVersion(char *buffer, const char *last) const
+	char *LogOSVersion(char *buffer, const char *last) const override
 	{
 		struct utsname name;
 		if (uname(&name) < 0) {
@@ -60,7 +60,7 @@ class CrashLogUnix : public CrashLog {
 		);
 	}
 
-	/* virtual */ char *LogError(char *buffer, const char *last, const char *message) const
+	char *LogError(char *buffer, const char *last, const char *message) const override
 	{
 		return buffer + seprintf(buffer, last,
 				"Crash reason:\n"
@@ -105,7 +105,7 @@ class CrashLogUnix : public CrashLog {
 	}
 #endif
 
-	/* virtual */ char *LogStacktrace(char *buffer, const char *last) const
+	char *LogStacktrace(char *buffer, const char *last) const override
 	{
 		buffer += seprintf(buffer, last, "Stacktrace:\n");
 #if defined(__GLIBC__)