The patch titled
Subject: kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
has been added to the -mm tree. Its filename is
kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
Currently, kasan_free_nondeferred_pages()->kasan_free_pages() is called
after debug_pagealloc_unmap_pages(). This causes a crash when
debug_pagealloc is enabled, as HW_TAGS KASAN can't set tags on an unmapped
page.
This patch puts kasan_free_nondeferred_pages() before
debug_pagealloc_unmap_pages().
Besides fixing the crash, this also makes the annotation order consistent
with debug_pagealloc_map_pages() preceding kasan_alloc_pages().
Link: https://lkml.kernel.org/r/1aa83e48627978de8068d5e3314185f3a0d7a849.1614302398.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc
+++ a/mm/page_alloc.c
@@ -1288,10 +1288,14 @@ static __always_inline bool free_pages_p
*/
arch_free_page(page, order);
- debug_pagealloc_unmap_pages(page, 1 << order);
-
+ /*
+ * With hardware tag-based KASAN, memory tags must be set
+ * before unmapping the page with debug_pagealloc.
+ */
kasan_free_nondeferred_pages(page, order);
+ debug_pagealloc_unmap_pages(page, 1 << order);
+
return true;
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
