linux-kernel - [PATCH 2/5] x86_64: kasan: flush tlbs after switching cr3

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Date:	Tue, 30 Jun 2015 12:00:08 +0300
From:	Andrey Ryabinin <a.ryabinin@...sung.com>
To:	Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org
Cc:	Andrey Konovalov <adech.fo@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	Alexander Popov <alpopov@...ecurity.com>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	Alexander Potapenko <glider@...gle.com>,
	linux-kernel@...r.kernel.org,
	Andrey Ryabinin <a.ryabinin@...sung.com>,
	stable@...r.kernel.org
Subject: [PATCH 2/5] x86_64: kasan: flush tlbs after switching cr3

load_cr3() doesn't cause tlb_flush if PGE enabled.
This may cause tons of false positive reports spamming
kernel to death.
To fix this __flush_tlb_all() should be called explicitly
after cr3 changed.

Signed-off-by: Andrey Ryabinin <a.ryabinin@...sung.com>
Cc: <stable@...r.kernel.org> # 4.0
---
 arch/x86/mm/kasan_init_64.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 0e4a05f..5d26642 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -208,6 +208,7 @@ void __init kasan_init(void)
 
 	memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt));
 	load_cr3(early_level4_pgt);
+	__flush_tlb_all();
 
 	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
 
@@ -234,5 +235,6 @@ void __init kasan_init(void)
 	memset(kasan_zero_page, 0, PAGE_SIZE);
 
 	load_cr3(init_level4_pgt);
+	__flush_tlb_all();
 	init_task.kasan_depth = 0;
 }
-- 
2.4.4

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