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

From: <yee.lee@mediatek.com>
To: <andreyknvl@gmail.com>
Cc: <wsd_upstream@mediatek.com>, Yee Lee <yee.lee@mediatek.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-arm-kernel@lists.infradead.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>
Subject: [PATCH v3 0/1] kasan: fix redzone overwritten issue under SLUB debug
Date: Wed, 30 Jun 2021 21:49:39 +0800	[thread overview]
Message-ID: <20210630134943.20781-1-yee.lee@mediatek.com> (raw)

From: Yee Lee <yee.lee@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(+)

-- 
2.18.0
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