On Fri, Sep 27, 2019 at 05:15:08PM -0400, Qian Cai wrote: > On Fri, 2019-09-27 at 13:48 -0700, Andrew Morton wrote: > > On Fri, 27 Sep 2019 15:47:03 -0400 Qian Cai <cai@xxxxxx> wrote: > > > --- a/mm/page_alloc.c > > > +++ b/mm/page_alloc.c > > > @@ -1175,11 +1175,11 @@ static __always_inline bool free_pages_prepare(struct page *page, > > > debug_check_no_obj_freed(page_address(page), > > > PAGE_SIZE << order); > > > } > > > - arch_free_page(page, order); > > > if (want_init_on_free()) > > > kernel_init_free_pages(page, 1 << order); > > > > > > kernel_poison_pages(page, 1 << order, 0); > > > + arch_free_page(page, order); > > > if (debug_pagealloc_enabled()) > > > kernel_map_pages(page, 1 << order, 0); > > > > This is all fairly mature code, isn't it? What happened to make this > > problem pop up now? > > In the past, there is only kernel_poison_pages() would trigger it but it needs > "page_poison=on" kernel cmdline, and I suspect nobody tested that on s390 in the > past. Yes. Peter Oberparleiter reported this also before my short vacation, but I didn't have time to look into this. Thanks for fixing! Reviewed-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
