The patch titled
Subject: kasan: add memzero init for unaligned size under SLUB debug
has been added to the -mm tree. Its filename is
kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
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------------------------------------------------------
From: Yee Lee <yee.lee@xxxxxxxxxxxx>
Subject: kasan: add memzero init for unaligned size under SLUB debug
Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite the
redzone of object with unaligned size.
An additional memzero_explicit() path is added to replacing init by hwtag
instruction for those unaligned size at SLUB debug mode.
Link: https://lkml.kernel.org/r/20210624112624.31215-2-yee.lee@xxxxxxxxxxxx
Signed-off-by: Yee Lee <yee.lee@xxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan.h | 6 ++++++
1 file changed, 6 insertions(+)
--- a/mm/kasan/kasan.h~kasan-add-memzero-init-for-unaligned-size-under-slub-debug
+++ a/mm/kasan/kasan.h
@@ -387,6 +387,12 @@ static inline void kasan_unpoison(const
if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
return;
+#if IS_ENABLED(CONFIG_SLUB_DEBUG)
+ if (init && ((unsigned long)size & KASAN_GRANULE_MASK)) {
+ init = false;
+ memzero_explicit((void *)addr, size);
+ }
+#endif
size = round_up(size, KASAN_GRANULE_SIZE);
hw_set_mem_tag_range((void *)addr, size, tag, init);
_
Patches currently in -mm which might be from yee.lee@xxxxxxxxxxxx are
kasan-add-memzero-init-for-unaligned-size-under-slub-debug.patch
