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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 27/75] x86/uaccess, kcov: Disable stack protector
Date:   Mon, 17 Jun 2019 23:09:38 +0200
Message-Id: <20190617210753.885928021@linuxfoundation.org>
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[ Upstream commit 40ea97290b08be2e038b31cbb33097d1145e8169 ]

New tooling noticed this mishap:

  kernel/kcov.o: warning: objtool: write_comp_data()+0x138: call to __stack_chk_fail() with UACCESS enabled
  kernel/kcov.o: warning: objtool: __sanitizer_cov_trace_pc()+0xd9: call to __stack_chk_fail() with UACCESS enabled

All the other instrumentation (KASAN,UBSAN) also have stack protector
disabled.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/Makefile b/kernel/Makefile
index 7a63d567fdb5..df5e3ca30acd 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -30,6 +30,7 @@ KCOV_INSTRUMENT_extable.o := n
 # Don't self-instrument.
 KCOV_INSTRUMENT_kcov.o := n
 KASAN_SANITIZE_kcov.o := n
+CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
 
 # cond_syscall is currently not LTO compatible
 CFLAGS_sys_ni.o = $(DISABLE_LTO)
-- 
2.20.1