Messages in this thread Patch in this message | | | Date | Tue, 30 Mar 2021 17:31:54 +0200 | Subject | [PATCH mm] mm, kasan: fix for "integrate page_alloc init with HW_TAGS" | From | Andrey Konovalov <> |
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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@suse.cz> Reported-by: Sergei Trofimovich <slyfox@gentoo.org> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- 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
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