Re: [PATCH v3 6/9] module: switch to execmem API for remapping as RW and restoring ROX

Petr Pavlu
2025-01-27T12:50:35Z

On 1/26/25 08:47, Mike Rapoport wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
>
> Instead of using writable copy for module text sections, temporarily remap
> the memory allocated from execmem's ROX cache as writable and restore its
> ROX permissions after the module is formed.
>
> This will allow removing nasty games with writable copy in alternatives
> patching on x86.
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

[...]

> +static void module_memory_restore_rox(struct module *mod)
> +{
> + for_class_mod_mem_type(type, text) {
> + struct module_memory *mem = &mod->mem[type];
> +
> + if (mem->is_rox)
> + execmem_restore_rox(mem->base, mem->size);
> + }
> +}
> +

Can the execmem_restore_rox() call here fail? I realize that there isn't
much that the module loader can do if that happens, but should it be
perhaps logged as a warning?

--
Thanks,
Petr