Re: [PATCH v5 3/3] mm/khugepaged: maintain page cache uptodate flag

[Matthew Wilcox]

On Thu, Mar 23, 2023 at 12:07:46PM -0700, Hugh Dickins wrote:
> On an earlier audit, for different reasons, I did also run across
> lib/buildid.c build_id_parse() using find_get_page() without checking
> PageUptodate() - looks as if it might do the wrong thing if it races
> with khugepaged collapsing text to huge, and should probably have a
> similar fix.

That shouldn't be using find_get_page().  It should probably use
read_cache_folio() which will actually read in the data if it's not
present in the page cache, and return an ERR_PTR if the data couldn't
be read.