properly zero memory on demand paging and mmap

src/sys/mm/vmm.c

@@ -580,6 +580,8 @@ bool vmm_dealwithrequest(void* addr, long error, bool user){
 	
 	status = true;
 	
+	memset(addr, 0, PAGE_SIZE);
+
 	done:
 
 	spinlock_release(lock);

src/sys/syscalls/mmap.c

@@ -84,14 +84,14 @@ syscallret syscall_mmap(void* hint, size_t len, int prot, int flags, int fd, off
 	if(ret == NULL && (flags & MAP_FIXED) == 0)
 		ret = vmm_allocfrom(USER_ALLOC_START, mmuflags, plen);
 
-	if(!ret){
+	if(!ret)
 		retv.errno = ENOMEM;
-		if(flags & MAP_ANON)
-			memset(ret, 0, plen);
-	}
-	else
+	else{
 		retv.ret = ret;
-
+		if(hint && (flags & MAP_ANON))
+			memset(ret, 0, plen*PAGE_SIZE);
+	}
+	
 	return retv;
 
 }