On Wed, Feb 26, 2025 at 06:48:15AM -0500, Brian Geffon wrote: > When handling faults for anon shmem finish_fault() will attempt to install > ptes for the entire folio. Unfortunately if it encounters a single > non-pte_none entry in that range it will bail, even if the pte that > triggered the fault is still pte_none. When this situation happens the > fault will be retried endlessly never making forward progress. > > This patch fixes this behavior and if it detects that a pte in the range > is not pte_none it will fall back to setting just the pte for the > address that triggered the fault. Surely there's a similar problem in do_anonymous_page()? At any rate, what a horrid function finish_fault() has become. Special cases all over the place. What we should be doing is deciding the range of PTEs to insert, bounded by the folio, the VMA and any non-none entries. Maybe I'll get a chance to fix this up.
