On Tue, Feb 7, 2023 at 7:20 PM Jiaqi Yan <jiaqiyan@xxxxxxxxxx> wrote: > > Pinging KMSAN experts, for the general guidance of > kmsan_copy_page_meta vs kmsan_unpoison_memory Oh, sorry, I've missed the previous email. copy_mc_user_highpage() is expected to copy data from the user page, for which no metadata is ever allocated. Therefore we just initialize the destination shadow with zeros instead of copying anything. kmsan_copy_page_meta() is used when the metadata is copied between two kernel pages, therefore it handles the cases when page->kmsan_shadow is NULL for the source and destination pages. It might be a good idea to use kmsan_copy_page_meta() in both cases, but to do that I want to better understand what happens when kmap_local_page(from) is called in copy_mc_user_highpage(). Where does the corresponding struct page come from?
