Re: [PATCH v2] mm: Track page table modifications in __apply_to_page_range()

On Fri, 21 Aug 2020 14:37:46 +0200 Joerg Roedel joro@8bytes.org wrote:

The __apply_to_page_range() function is also used to change and/or allocate page-table pages in the vmalloc area of the address space. Make sure these changes get synchronized to other page-tables in the system by calling arch_sync_kernel_mappings() when necessary.

There's no description here of the user-visible effects of the bug. Please always provide this, especially when proposing a -stable backport. Take pity upon all the downstream kernel maintainers who are staring at this wondering whether they should risk adding it to their kernels.