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WDCIronportException: Internal
From:   Naohiro Aota <naohiro.aota@wdc.com>
To:     linux-mm@kvack.org, akpm@linux-foundation.org, x86@kernel.org
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Naohiro Aota <naohiro.aota@wdc.com>,
        Anshuman Khandual <anshuman.khandual@arm.com>
Subject: [PATCH] x86/mm: disable instrumentations of mm/pgprot.c
Date:   Wed, 24 Aug 2022 17:47:26 +0900
Message-Id: <20220824084726.2174758-1-naohiro.aota@wdc.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The commit 4867fbbdd6b3 ("x86/mm: move protection_map[] inside the
platform") moved accesses to protection_map[] from mem_encrypt_amd.c to
pgprot.c. As a result, the accesses are now targets of KASAN (and other
instrumentations), leading to the crash during the boot process.

Disable the instrumentations for pgprot.c like commit 67bb8e999e0a
("x86/mm: Disable various instrumentations of mm/mem_encrypt.c and
mm/tlb.c").

Before this patch, my AMD machine cannot boot since v6.0-rc1 with KASAN
enabled, without anything printed. After the change, it successfully boots
up.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 arch/x86/mm/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index f8220fd2c169..829c1409ffbd 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -4,10 +4,12 @@ KCOV_INSTRUMENT_tlb.o			:= n
 KCOV_INSTRUMENT_mem_encrypt.o		:= n
 KCOV_INSTRUMENT_mem_encrypt_amd.o	:= n
 KCOV_INSTRUMENT_mem_encrypt_identity.o	:= n
+KCOV_INSTRUMENT_pgprot.o		:= n
 
 KASAN_SANITIZE_mem_encrypt.o		:= n
 KASAN_SANITIZE_mem_encrypt_amd.o	:= n
 KASAN_SANITIZE_mem_encrypt_identity.o	:= n
+KASAN_SANITIZE_pgprot.o		:= n
 
 # Disable KCSAN entirely, because otherwise we get warnings that some functions
 # reference __initdata sections.
@@ -17,6 +19,7 @@ ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_mem_encrypt.o		= -pg
 CFLAGS_REMOVE_mem_encrypt_amd.o		= -pg
 CFLAGS_REMOVE_mem_encrypt_identity.o	= -pg
+CFLAGS_REMOVE_pgprot.o			= -pg
 endif
 
 obj-y				:=  init.o init_$(BITS).o fault.o ioremap.o extable.o mmap.o \
-- 
2.37.2