Provided are a method, system, and program for sharing data in a user virtual address range with a kernel virtual address range. A user address in a user address space and length defining a user address range referencing physical locations in a memory are received. A determination is made of determining at least one page in the memory including the physical locations referenced by the user address range. For each determined page, one kernel address in a kernel address space is generated to reference the determined page, wherein at least one user address and at least one kernel address reference one page in the memory.