Index: sys/compat/linuxkpi/common/include/linux/kernel.h
===================================================================
--- sys/compat/linuxkpi/common/include/linux/kernel.h
+++ sys/compat/linuxkpi/common/include/linux/kernel.h
@@ -138,11 +138,6 @@
 extern void linux_dump_stack(void);
 #define	dump_stack()		linux_dump_stack()
 
-struct va_format {
-	const char *fmt;
-	va_list *va;
-};
-
 static inline int
 vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 {
Index: sys/kern/subr_prf.c
===================================================================
--- sys/kern/subr_prf.c
+++ sys/kern/subr_prf.c
@@ -665,6 +665,7 @@
 	char nbuf[MAXNBUF];
 	char *d;
 	const char *p, *percent, *q;
+	struct va_format *vaf;
 	u_char *up;
 	int ch, n, sign;
 	uintmax_t num;
@@ -819,11 +820,35 @@
 			base = 8;
 			goto handle_nosign;
 		case 'p':
-			base = 16;
-			sharpflag = (width == 0);
-			sign = 0;
-			num = (uintptr_t)va_arg(ap, void *);
-			goto number;
+			switch (*fmt) {
+			case 'V':
+				fmt++;
+
+				vaf = va_arg(ap, struct va_format *);
+				if (vaf == NULL) {
+					p = "(null)";
+					n = strlen(p);
+					while (n--)
+						PCHAR(*p++);
+					break;
+				}
+
+				if (func) {
+					retval += kvprintf(vaf->fmt, func, arg, radix,
+					    *vaf->va);
+				} else {
+					retval += kvprintf(vaf->fmt, NULL, d, radix,
+					    *vaf->va);
+				}
+				break;
+			default:
+				base = 16;
+				sharpflag = (width == 0);
+				sign = 0;
+				num = (uintptr_t)va_arg(ap, void *);
+				goto number;
+			}
+			break;
 		case 'q':
 			qflag = 1;
 			goto reswitch;
Index: sys/sys/systm.h
===================================================================
--- sys/sys/systm.h
+++ sys/sys/systm.h
@@ -251,6 +251,11 @@
 #define	HD_OMIT_HEX	(1 << 17)
 #define	HD_OMIT_CHARS	(1 << 18)
 
+struct va_format {
+	const char	*fmt;
+	__va_list	*va;
+};
+
 #define ovbcopy(f, t, l) bcopy((f), (t), (l))
 void	explicit_bzero(void * _Nonnull, size_t);