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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, Nathan Chancellor <nathan@kernel.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 136/240] x86/events/amd/iommu: Fix sysfs type mismatch
Date:   Thu, 20 May 2021 11:22:08 +0200
Message-Id: <20210520092113.218389518@linuxfoundation.org>
In-Reply-To: <20210520092108.587553970@linuxfoundation.org>
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From: Nathan Chancellor <nathan@kernel.org>

[ Upstream commit de5bc7b425d4c27ae5faa00ea7eb6b9780b9a355 ]

dev_attr_show() calls _iommu_event_show() via an indirect call but
_iommu_event_show()'s 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_iommu_1/events/mem_dte_hit
csource=0x0a

$ dmesg | grep "CFI failure"
[ 3526.735140] CFI failure (target: _iommu_event_show...):

Change _iommu_event_show() and 'struct amd_iommu_event_desc' to
'struct device_attribute' so that there is no more CFI violation.

Fixes: 7be6296fdd75 ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210415001112.3024673-1-nathan@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/events/amd/iommu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c
index b28200dea715..2bbf3fba8097 100644
--- a/arch/x86/events/amd/iommu.c
+++ b/arch/x86/events/amd/iommu.c
@@ -80,12 +80,12 @@ static struct attribute_group amd_iommu_format_group = {
  * sysfs events attributes
  *---------------------------------------------*/
 struct amd_iommu_event_desc {
-	struct kobj_attribute attr;
+	struct device_attribute attr;
 	const char *event;
 };
 
-static ssize_t _iommu_event_show(struct kobject *kobj,
-				struct kobj_attribute *attr, char *buf)
+static ssize_t _iommu_event_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
 {
 	struct amd_iommu_event_desc *event =
 		container_of(attr, struct amd_iommu_event_desc, attr);
-- 
2.30.2