On Tue, 30 Mar 2021 18:44:09 +0200 Vlastimil Babka <vba...@suse.cz> wrote:
> On 3/30/21 6:37 PM, Andrey Konovalov wrote: > > My commit "integrate page_alloc init with HW_TAGS" changed the order of > > kernel_unpoison_pages() and kernel_init_free_pages() calls. This leads > > to complaints from the page unpoisoning code, as the poison pattern gets > > overwritten for __GFP_ZERO allocations. > > > > Fix by restoring the initial order. Also add a warning comment. > > > > Reported-by: Vlastimil Babka <vba...@suse.cz> > > Reported-by: Sergei Trofimovich <sly...@gentoo.org> > > Signed-off-by: Andrey Konovalov <andreyk...@google.com> > > Tested that the bug indeed occurs in -next and is fixed by this. Thanks. Reviewed-by: Sergei Trofimovich <sly...@gentoo.org> > > --- > > mm/page_alloc.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 033bd92e8398..d2c020563c0b 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -2328,6 +2328,13 @@ inline void post_alloc_hook(struct page *page, > > unsigned int order, > > arch_alloc_page(page, order); > > debug_pagealloc_map_pages(page, 1 << order); > > > > + /* > > + * Page unpoisoning must happen before memory initialization. > > + * Otherwise, the poison pattern will be overwritten for __GFP_ZERO > > + * allocations and the page unpoisoning code will complain. > > + */ > > + kernel_unpoison_pages(page, 1 << order); > > + > > /* > > * As memory initialization might be integrated into KASAN, > > * kasan_alloc_pages and kernel_init_free_pages must be > > @@ -2338,7 +2345,6 @@ inline void post_alloc_hook(struct page *page, > > unsigned int order, > > if (init && !kasan_has_integrated_init()) > > kernel_init_free_pages(page, 1 << order); > > > > - kernel_unpoison_pages(page, 1 << order); > > set_page_owner(page, order, gfp_flags); > > } > > > > > -- Sergei
