Hello, After compiling kernel 2.1.21, when trying to boot the kernel, I got the following error (the computer hang afterwards): Unable to handle NULL pointer dereference at virtual address 00000000 current->tss.cr3=00101000 %cr3=00101000 *pde=00000000 Oops: 0000 CPU: 0 EIP: 0010:[<0012b238>]