On 10.07.23 10:32, Linke Li wrote:
From: Linke Li <lilinke99@xxxxxxxxx> vma_len = (loff_t)(vma->vm_end - vma->vm_start); len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); /* check for overflow */ if (len < vma_len) return -EINVAL; The existing code includes an integer overflow check, which indicates that the variable len has the potential to overflow, leading to undefined behavior according to the C standard. However, both GCC and Clang compilers may eliminate this overflow check based on the assumption that there will be no undefined behavior. Although the Linux kernel disables these optimizations by using the -fno-strict-overflow option, there is still a risk if the compilers make mistakes in the future.
So we're adding code to handle eventual future compiler bugs? That sounds wrong, but maybe I misunderstood the problem you are trying to solve?
-- Cheers, David / dhildenb
