Dynamic memory allocation in XV6 kernel

I want to implement a Queue struct (using Node struct, similiral to the C code here) in files Queue.c and Queue.h in order to store processes in proc.c in XV6 kernel.

I don't know how to to do it, since it requires to use malloc, but I can't use it inside methods which I call from the kernel.

What can I use instead, in order to implement and use the Queue?