Linux Kernel Empty Range Invalidation Vulnerability in mremap() System Call

A vulnerability in the Linux kernel's memory management can lead to unnecessary warnings in KVM's memory management unit notifier. This issue arises when the mremap() system call is used with an old_size of zero, causing the move_page_tables() function to invoke invalidate_range_start() and invalidate_range_end() with an empty range. Such empty ranges have previously been flagged as off-by-one errors, triggering a warning. Although there have been few unique reports of this issue, it is considered beneficial to identify and correct these erroneous usages in userspace.

Impact

The vulnerability causes unnecessary warnings in KVM's memory management unit notifier, which can disrupt normal operations and performance.