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authorseokhoon.yoon <iamyooon@gmail.com>2016-05-20 16:58:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 17:58:30 -0700
commit29b52de182acf50f85a8284ad39104d84c9bbf57 (patch)
tree79b8aa6e41e9107ef1c71eee4f0285d81fc0d80b /mm
parentd0834a6c2c5b0c76cfb806bd7dba6556d8b4edbb (diff)
downloadlinux-29b52de182acf50f85a8284ad39104d84c9bbf57.tar.bz2
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@gmail.com Signed-off-by: seokhoon.yoon <iamyooon@gmail.com> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Laura Abbott <labbott@fedoraproject.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2dd1ba4e70cc..383b14b4f61d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -993,7 +993,6 @@ static __always_inline bool free_pages_prepare(struct page *page,
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_prepare(struct page *page,
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;
}