[PATCH 2/2] perf/amd/uncore: Fix sysfs type mismatch

From: Nathan Chancellor <nathan@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com,
	Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH 2/2] perf/amd/uncore: Fix sysfs type mismatch
Date: Wed, 14 Apr 2021 17:11:12 -0700	[thread overview]
Message-ID: <20210415001112.3024673-2-nathan@kernel.org> (raw)
In-Reply-To: <20210415001112.3024673-1-nathan@kernel.org>

dev_attr_show() calls the __uncore_*_show() functions via an indirect
call but their type does not currently match the type of the show()
member in 'struct device_attribute', resulting in a Control Flow
Integrity violation.

$ cat /sys/devices/amd_l3/format/umask
config:8-15

$ dmesg | grep "CFI failure"
[ 1258.174653] CFI failure (target: __uncore_umask_show...):

Update the type in the DEFINE_UNCORE_FORMAT_ATTR macro to match
'struct device_attribute' so that there is no more CFI violation.

Link: https://github.com/ClangBuiltLinux/linux/issues/1350
Fixes: 06f2c24584f3 ("perf/amd/uncore: Prepare to scale for more attributes that vary per family")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 7f014d450bc2..582c0ffb5e98 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -275,14 +275,14 @@ static struct attribute_group amd_uncore_attr_group = {
 };
 
 #define DEFINE_UNCORE_FORMAT_ATTR(_var, _name, _format)			\
-static ssize_t __uncore_##_var##_show(struct kobject *kobj,		\
-				struct kobj_attribute *attr,		\
+static ssize_t __uncore_##_var##_show(struct device *dev,		\
+				struct device_attribute *attr,		\
 				char *page)				\
 {									\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
-static struct kobj_attribute format_attr_##_var =			\
+static struct device_attribute format_attr_##_var =			\
 	__ATTR(_name, 0444, __uncore_##_var##_show, NULL)
 
 DEFINE_UNCORE_FORMAT_ATTR(event12,	event,		"config:0-7,32-35");
-- 
2.31.1.272.g89b43f80a5

