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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, Colin Ian King <colin.king@canonical.com>,
        Leon Romanovsky <leonro@nvidia.com>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 60/94] gcov: add support for GCC 10.1
Date:   Mon, 21 Sep 2020 18:27:47 +0200
Message-Id: <20200921162038.301152872@linuxfoundation.org>
In-Reply-To: <20200921162035.541285330@linuxfoundation.org>
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From: Peter Oberparleiter <oberpar@linux.ibm.com>

[ Upstream commit 40249c6962075c040fd071339acae524f18bfac9 ]

Using gcov to collect coverage data for kernels compiled with GCC 10.1
causes random malfunctions and kernel crashes.  This is the result of a
changed GCOV_COUNTERS value in GCC 10.1 that causes a mismatch between
the layout of the gcov_info structure created by GCC profiling code and
the related structure used by the kernel.

Fix this by updating the in-kernel GCOV_COUNTERS value.  Also re-enable
config GCOV_KERNEL for use with GCC 10.

Reported-by: Colin Ian King <colin.king@canonical.com>
Reported-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Tested-by: Leon Romanovsky <leonro@nvidia.com>
Tested-and-Acked-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/gcov/Kconfig   | 1 -
 kernel/gcov/gcc_4_7.c | 4 +++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 1d78ed19a3512..1276aabaab550 100644
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -3,7 +3,6 @@ menu "GCOV-based kernel profiling"
 config GCOV_KERNEL
 	bool "Enable gcov-based kernel profiling"
 	depends on DEBUG_FS
-	depends on !CC_IS_GCC || GCC_VERSION < 100000
 	select CONSTRUCTORS if !UML
 	default n
 	---help---
diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c
index ca5e5c0ef8536..5b9e76117ded1 100644
--- a/kernel/gcov/gcc_4_7.c
+++ b/kernel/gcov/gcc_4_7.c
@@ -19,7 +19,9 @@
 #include <linux/vmalloc.h>
 #include "gcov.h"
 
-#if (__GNUC__ >= 7)
+#if (__GNUC__ >= 10)
+#define GCOV_COUNTERS			8
+#elif (__GNUC__ >= 7)
 #define GCOV_COUNTERS			9
 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
 #define GCOV_COUNTERS			10
-- 
2.25.1