diff --git a/sys/kern/kern_ktr.c b/sys/kern/kern_ktr.c
index cde019a509d0..3f00c8d03411 100644
--- a/sys/kern/kern_ktr.c
+++ b/sys/kern/kern_ktr.c
@@ -108,11 +108,12 @@ SYSCTL_INT(_debug_ktr, OID_AUTO, verbose, CTLFLAG_RW, &ktr_verbose, 0, "");
 #ifdef KTR
 #ifdef KTR_EXTEND
 void
-ktr_tracepoint(u_int mask, char *filename, u_int line, char *format, ...)
+ktr_tracepoint(u_int mask, const char *filename, u_int line,
+	       const char *format, ...)
 #else
 void
-ktr_tracepoint(u_int mask, char *format, u_long arg1, u_long arg2, u_long arg3,
-	       u_long arg4, u_long arg5)
+ktr_tracepoint(u_int mask, const char *format, u_long arg1, u_long arg2,
+	       u_long arg3, u_long arg4, u_long arg5)
 #endif
 {
 	struct ktr_entry *entry;
@@ -147,8 +148,7 @@ ktr_tracepoint(u_int mask, char *format, u_long arg1, u_long arg2, u_long arg3,
 	else
 		nanotime(&entry->ktr_tv);
 #ifdef KTR_EXTEND
-	strncpy(entry->ktr_filename, filename, KTRFILENAMESIZE - 1);
-	entry->ktr_filename[KTRFILENAMESIZE - 1] = '\0';
+	entry->ktr_filename = filename;
 	entry->ktr_line = line;
 	entry->ktr_cpu = KTR_CPU;
 	va_start(ap, format);
diff --git a/sys/sys/ktr.h b/sys/sys/ktr.h
index bf3ce5243d03..050b303eae44 100644
--- a/sys/sys/ktr.h
+++ b/sys/sys/ktr.h
@@ -96,15 +96,12 @@ struct ktr_entry {
 #ifndef KTRDESCSIZE
 #define KTRDESCSIZE 80
 #endif
-#ifndef KTRFILENAMESIZE
-#define KTRFILENAMESIZE 32
-#endif
-	char	ktr_desc [KTRDESCSIZE];
-	char    ktr_filename [KTRFILENAMESIZE];
+	char	ktr_desc[KTRDESCSIZE];
+	const	char *ktr_filename;
 	int	ktr_line;
 	int	ktr_cpu;
 #else
-	char	*ktr_desc;
+	const	char *ktr_desc;
 	u_long	ktr_parm1;
 	u_long	ktr_parm2;
 	u_long	ktr_parm3;
@@ -132,10 +129,10 @@ extern struct ktr_entry ktr_buf[];
 #endif
 
 #ifdef KTR_EXTEND
-void	ktr_tracepoint(u_int mask, char *filename, u_int line,
-		       char *format, ...) __printflike(4, 5);
+void	ktr_tracepoint(u_int mask, const char *filename, u_int line,
+		       const char *format, ...) __printflike(4, 5);
 #else
-void	ktr_tracepoint(u_int mask, char *format, u_long arg1, u_long arg2,
+void	ktr_tracepoint(u_int mask, const char *format, u_long arg1, u_long arg2,
 		       u_long arg3, u_long arg4, u_long arg5);
 #endif