[PATCH v3 0/1] kasan: fix redzone overwritten issue under SLUB debug

yee.lee at mediatek.com yee.lee at mediatek.com
Wed Jun 30 06:49:39 PDT 2021

From: Yee Lee <yee.lee at mediatek.com>

Issue: In SLUB debug, hwtag kasan_unpoison() would overwrite the redzone
 in those objects with unaligned size.

This patch Adds memzero_explict() to separate the initialization for
such condition. The new code path is executed about 1.1% during nromal
booting process. The penalty is acceptable since it only works in debug mode.

Exp: QEMUv5.2(+mte)/SLUB_debug mode
code path exec : 941/80854 (1.1%)
Changed since v2:
 - Use if-statement to refine the condition block instead of preprocessor #if
 - Add comment block about this new code path in source code.

Changed since v1:
 - Apply IS_ENABLED to wrap codes under SLUB debug mode.
 - Replace memset() by memzero_explict().


Yee Lee (1):
  kasan: Add memzero init for unaligned size under SLUB debug

 mm/kasan/kasan.h | 10 ++++++++++
 1 file changed, 10 insertions(+)


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