From: "seokhoon.yoon" <iamyooon@xxxxxxxxx> Subject: mm, kasan: fix to call kasan_free_pages() after poisoning page When CONFIG_PAGE_POISONING and CONFIG_KASAN is enabled, free_pages_prepare()'s codeflow is below. 1)kmemcheck_free_shadow() 2)kasan_free_pages() - set shadow byte of page is freed 3)kernel_poison_pages() 3.1) check access to page is valid or not using kasan ---> error occur, kasan think it is invalid access 3.2) poison page 4)kernel_map_pages() So kasan_free_pages() should be called after poisoning the page. Link: http://lkml.kernel.org/r/1463220405-7455-1-git-send-email-iamyooon@xxxxxxxxx Signed-off-by: seokhoon.yoon <iamyooon@xxxxxxxxx> Cc: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> Cc: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/page_alloc.c~mm-kasan-fix-to-call-kasan_free_pages-after-poisoning-page mm/page_alloc.c --- a/mm/page_alloc.c~mm-kasan-fix-to-call-kasan_free_pages-after-poisoning-page +++ a/mm/page_alloc.c @@ -993,7 +993,6 @@ static __always_inline bool free_pages_p trace_mm_page_free(page, order); kmemcheck_free_shadow(page, order); - kasan_free_pages(page, order); /* * Check tail pages before head page information is cleared to @@ -1035,6 +1034,7 @@ static __always_inline bool free_pages_p arch_free_page(page, order); kernel_poison_pages(page, 1 << order, 0); kernel_map_pages(page, 1 << order, 0); + kasan_free_pages(page, order); return true; } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
