CVE-2022-49077

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0)<br /> <br /> If an mremap() syscall with old_size=0 ends up in move_page_tables(), it<br /> will call invalidate_range_start()/invalidate_range_end() unnecessarily,<br /> i.e. with an empty range.<br /> <br /> This causes a WARN in KVM&amp;#39;s mmu_notifier. In the past, empty ranges<br /> have been diagnosed to be off-by-one bugs, hence the WARNing. Given the<br /> low (so far) number of unique reports, the benefits of detecting more<br /> buggy callers seem to outweigh the cost of having to fix cases such as<br /> this one, where userspace is doing something silly. In this particular<br /> case, an early return from move_page_tables() is enough to fix the<br /> issue.