From 1dd167be9f12524276d461892b8187aec8a7749d Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Tue, 30 Mar 2021 18:37:36 +0200 Subject: [PATCH] ANDROID: mm, kasan: fix for "integrate page_alloc init with HW_TAGS" 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 Reported-by: Sergei Trofimovich Signed-off-by: Andrey Konovalov Reviewed-by: Sergei Trofimovich The fix was included in upstream patch 1bb5eab30d68 'kasan, mm: integrate page_alloc init with HW_TAGS' Fixes: a15989497e64 ("FROMGIT: kasan, mm: integrate page_alloc init with HW_TAGS") Bug: 192912968 Signed-off-by: Suren Baghdasaryan Change-Id: Ifc4ab7ed27b3c060f70ba5ca03117a36c9b4da08 --- 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 cdebaa666ece..2080cf3d3b6d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2359,6 +2359,13 @@ 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 @@ -2375,7 +2382,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order, gfp_flags & __GFP_ZEROTAGS); } - kernel_unpoison_pages(page, 1 << order); set_page_owner(page, order, gfp_flags); }