Help please.

[Zibri]

Hello!
I am writing a kernel module that patches a kernel function on ARM64 (android).
The problem is that as I write the 8 bytes I need to write, kernel crashes and reboots.
I have seen you are using update_mapping_prot but I don't understand how to use it to make RW the function code.

For example, let's say I want to change 8 bytes in function ip_forward.
I get the address to modify in a variable like this:

unsigned long *ff;
..........
ff=findcode();
printk("Found code at: %lx\n",ff);

to write it I do:
ff[0]=0xd503201fd503201f; // two nops
or
*ff = 0xd503201fd503201f; // two nops

how can I make the kernel code section where ip_forward is RW before the write?

[m0nad]

This part was written by @awerv, which can help you better.