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 __GFP_ZERO allocations being incorrectly poisoned when page poisoning is enabled. Fix by restoring the initial order. Also add a warning comment. Reported-by: Vlastimil Babka <vbabka@xxxxxxx> Reported-by: Sergei Trofimovich <slyfox@xxxxxxxxxx> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> --- mm/page_alloc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 033bd92e8398..1fc5061f8ca1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2328,6 +2328,12 @@ 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, a __GFP_ZERO allocation will not be initialized. + */ + 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 +2344,6 @@ 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); } -- 2.31.0.291.g576ba9dcdaf-goog
