On Wed, Jun 05, 2024 at 03:05:43PM -0700, Andrew Morton wrote: > On Wed, 5 Jun 2024 17:21:46 -0400 Peter Xu <peterx@xxxxxxxxxx> wrote: > > > Not all pages may apply to pgtable check. One example is ZONE_DEVICE > > pages: they map PFNs directly, and they don't allocate page_ext at all even > > if there's struct page around. One may reference devm_memremap_pages(). > > > > When both ZONE_DEVICE and page-table-check enabled, then try to map some > > dax memories, one can trigger kernel bug constantly now when the kernel was > > trying to inject some pfn maps on the dax device: > > > > kernel BUG at mm/page_table_check.c:55! > > > > While it's pretty legal to use set_pxx_at() for ZONE_DEVICE pages for page > > fault resolutions, skip all the checks if page_ext doesn't even exist in > > pgtable checker, which applies to ZONE_DEVICE but maybe more. > > Do we have a Reported-by: for this one? Nop, I just hit that when I started to look at the dax issues. > > And a Fixes? It looks like df4e817b7108? Yes that commit should be proper. Thanks, -- Peter Xu
