On Sat, 6 Mar 2021 00:36:33 +0100 Andrey Konovalov andreyknvl@google.com wrote:
Currently, kasan_free_nondeferred_pages()->kasan_free_pages() is called after debug_pagealloc_unmap_pages(). This causes a crash when debug_pagealloc is enabled, as HW_TAGS KASAN can't set tags on an unmapped page.
This patch puts kasan_free_nondeferred_pages() before debug_pagealloc_unmap_pages() and arch_free_page(), which can also make the page unavailable.
...
--- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1304,6 +1304,12 @@ static __always_inline bool free_pages_prepare(struct page *page, kernel_poison_pages(page, 1 << order);
- /*
* With hardware tag-based KASAN, memory tags must be set before the* page becomes unavailable via debug_pagealloc or arch_free_page.*/- kasan_free_nondeferred_pages(page, order, fpi_flags);
- /*
- arch_free_page() can make the page's contents inaccessible. s390
- does this. So nothing which can access the page's contents should
@@ -1313,8 +1319,6 @@ static __always_inline bool free_pages_prepare(struct page *page, debug_pagealloc_unmap_pages(page, 1 << order);
- kasan_free_nondeferred_pages(page, order, fpi_flags);
- return true;
}
kasan_free_nondeferred_pages() has only two args in current mainline.
I fixed that in the obvious manner...