Hi Folks, A custom driver overrides (vm_operations_struct.fault) and map their compound page(__GFP_COMP) to page table on userprocess on demand. Here problem is page fault occur: __do_fault vma->vm_ops->fault <- driver returns their compould page finish_fault alloc_set_pte PageTransCompound(page) do_set_pmd map the page as THP page Since it's not a THP page, system goes random crash after a while due to conflict of VM THP handling with the driver compound page handling. Even though it happens in old kernel with backporting THP pagecache, I think it's still valid on recent kernel. What's the best way to fix it? Driver don't do that or VM need to deal with it? Thank you.
