On 1/21/25 10:57, Mike Rapoport wrote:
In order to use execmem's API for temporal remapping of the memory allocated from ROX cache as writable, there is a need to distinguish between the state when the module is being formed and the state when it is deconstructed and freed so that when module_memory_free() is called from error paths during module loading it could restore ROX mappings.
Replace open coded checks for MODULE_STATE_UNFORMED with a helper function module_is_formed() and add a new MODULE_STATE_GONE that will be set when the module is deconstructed and freed.
I don't fully follow why this case requires a new module state. My understanding it that the function load_module() has the necessary context that after calling layout_and_allocate(), the updated ROX mappings need to be restored. I would then expect the function to be appropriately able to unwind this operation in case of an error. It could be done by having a helper that walks the mappings and calls execmem_restore_rox(), or if you want to keep it in module_memory_free() as done in the patch #7 then a flag could be passed down to module_deallocate() -> free_mod_mem() -> module_memory_free()?
It is at least good that MODULE_STATE_GONE is only set in free_module() past the sysfs teardown, so it never shows in /sys/module/<mod>/initstate. Otherwise, this would require teaching kmod about this state as well.