On Fri, Jul 07, 2023 at 02:12:06PM -0400, David Wysochanski wrote: > I think myself / Daire Byrne may have already tracked this down and I > found a 1-liner that fixed a similar crash in his environment. > > Can you try this patch on top and let me know if it still crashes? > https://github.com/DaveWysochanskiRH/kernel/commit/902c990e311120179fa5de99d68364b2947b79ec Said one-liner: - struct address_space *mapping = folio->mapping; + struct address_space *mapping = folio_mapping(folio); This will definitely fix the problem. shrink_folio_list() sees anonymous folios as well as file folios. I wonder if we want to go a step further and introduce ... +static inline bool __folio_needs_release(struct address_space *mapping, + struct folio *folio) +{ + return folio_has_private(folio) || + (mapping && mapping_release_always(mapping)); +} + /* * Return true if a folio needs ->release_folio() calling upon it. */ static inline bool folio_needs_release(struct folio *folio) { - struct address_space *mapping = folio->mapping; - - return folio_has_private(folio) || - (mapping && mapping_release_always(mapping)); + return __folio_needs_release(folio_mapping(folio), folio); } since two of the three callers already have done the necessary dance to get the mapping (and they're the two which happen regularly; the third is an unusual situation).
