I have a singleton whose memory is being corrupted by an unknown corruptor. Something is overwriting the memory for the singleton, and hundreds of bytes around it, with value 0. After the object is constructed via new, it is read-only for the lifetime of the application.
I'd like to capture the corruptor at the time of the corruption. I'd like to mprotect as read-only the memory of the object after construction. That way later when the corruption happens the system will segmentation fault at the time of corruption.
It looks like mprotect is granular to the page level. How would I "over allocate" for the singleton instance a full page for the object (it is far smaller than 4k, the standard page size) and then mprotect that page?
You can use anonymous mmap to allocate a full page for the singleton, then construct the object into it with placement new.