Index: head/share/man/man9/malloc.9
===================================================================
--- head/share/man/man9/malloc.9
+++ head/share/man/man9/malloc.9
@@ -49,6 +49,8 @@
 .Fn mallocarray "size_t nmemb" "size_t size" "struct malloc_type *type" "int flags"
 .Ft void
 .Fn free "void *addr" "struct malloc_type *type"
+.Ft void
+.Fn zfree "void *addr" "struct malloc_type *type"
 .Ft void *
 .Fn realloc "void *addr" "size_t size" "struct malloc_type *type" "int flags"
 .Ft void *
@@ -105,6 +107,19 @@
 then
 .Fn free
 does nothing.
+.Pp
+Like
+.Fn free ,
+the
+.Fn zfree
+function releases memory at address
+.Fa addr
+that was previously allocated by
+.Fn malloc
+for re-use.
+However,
+.Fn zfree
+will zero the memory before it is released.
 .Pp
 The
 .Fn realloc
Index: head/sys/kern/kern_malloc.c
===================================================================
--- head/sys/kern/kern_malloc.c
+++ head/sys/kern/kern_malloc.c
@@ -820,6 +820,48 @@
 	malloc_type_freed(mtp, size);
 }
 
+/*
+ *	zfree:
+ *
+ *	Zero then free a block of memory allocated by malloc.
+ *
+ *	This routine may not block.
+ */
+void
+zfree(void *addr, struct malloc_type *mtp)
+{
+	uma_zone_t zone;
+	uma_slab_t slab;
+	u_long size;
+
+#ifdef MALLOC_DEBUG
+	if (free_dbg(&addr, mtp) != 0)
+		return;
+#endif
+	/* free(NULL, ...) does nothing */
+	if (addr == NULL)
+		return;
+
+	vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab);
+	if (slab == NULL)
+		panic("free: address %p(%p) has not been allocated.\n",
+		    addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
+
+	if (__predict_true(!malloc_large_slab(slab))) {
+		size = zone->uz_size;
+#ifdef INVARIANTS
+		free_save_type(addr, mtp, size);
+#endif
+		explicit_bzero(addr, size);
+		uma_zfree_arg(zone, addr, slab);
+	} else {
+		size = malloc_large_size(slab);
+		explicit_bzero(addr, size);
+		free_large(addr, size);
+	}
+	malloc_type_freed(mtp, size);
+}
+
 void
 free_domain(void *addr, struct malloc_type *mtp)
 {
Index: head/sys/sys/malloc.h
===================================================================
--- head/sys/sys/malloc.h
+++ head/sys/sys/malloc.h
@@ -179,6 +179,7 @@
 	    unsigned long alignment, vm_paddr_t boundary)
 	    __malloc_like __result_use_check __alloc_size(1) __alloc_align(7);
 void	free(void *addr, struct malloc_type *type);
+void	zfree(void *addr, struct malloc_type *type);
 void	free_domain(void *addr, struct malloc_type *type);
 void	*malloc(size_t size, struct malloc_type *type, int flags) __malloc_like
 	    __result_use_check __alloc_size(1);