diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -228,6 +228,16 @@
     CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, NULL, 0,
     sysctl_vm_malloc_zone_sizes, "S", "Zone sizes used by malloc");
 
+#ifdef MALLOC_DEBUG
+static uint64_t sysctl_panic_on_free_addr = 0;
+SYSCTL_U64(_vm_malloc, OID_AUTO, panic_on_free_addr, CTLFLAG_RW,
+    &sysctl_panic_on_free_addr, 0, "Panic if this address is freed");
+
+static uint64_t sysctl_printf_on_free_addr = 0;
+SYSCTL_U64(_vm_malloc, OID_AUTO, printf_on_free_addr, CTLFLAG_RW,
+    &sysctl_printf_on_free_addr, 0, "Printf if this address is freed");
+#endif
+
 /*
  * The malloc_mtx protects the kmemstatistics linked list.
  */
@@ -493,7 +503,12 @@
 void
 contigfree(void *addr, unsigned long size, struct malloc_type *type)
 {
-
+#ifdef MALLOC_DEBUG
+	if (sysctl_printf_on_free_addr != 0 && (uintptr_t)addr == (uintptr_t)sysctl_printf_on_free_addr)
+		printf("%s: REQUESTED PRINTF on freeing %p size %lu type %s\n", __func__, addr, size, type->ks_shortdesc);
+	if (sysctl_panic_on_free_addr != 0 && (uintptr_t)addr == (uintptr_t)sysctl_panic_on_free_addr)
+		panic("%s: REQUESTED PANIC on freeing %p size %lu type %s\n", __func__, addr, size, type->ks_shortdesc);
+#endif
 	kmem_free(addr, size);
 	malloc_type_freed(type, round_page(size));
 }
@@ -878,6 +893,11 @@
 	if (addr == NULL)
 		return (EJUSTRETURN);
 
+	if (sysctl_printf_on_free_addr != 0 && (uintptr_t)addr == (uintptr_t)sysctl_printf_on_free_addr)
+		printf("%s: REQUESTED PRINTF on freeing %p type %s\n", __func__, addr, mtp->ks_shortdesc);
+	if (sysctl_panic_on_free_addr != 0 && (uintptr_t)addr == (uintptr_t)sysctl_panic_on_free_addr)
+		panic("%s: REQUESTED PANIC on freeing %p type %s\n", __func__, addr, mtp->ks_shortdesc);
+
 #ifdef DEBUG_MEMGUARD
 	if (is_memguard_addr(addr)) {
 		memguard_free(addr);