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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, Hanjun Guo <guohanjun@huawei.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Will Deacon <will@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 59/91] ACPI/IORT: Fix off-by-one check in iort_dev_find_its_id()
Date:   Wed, 14 Aug 2019 19:01:22 +0200
Message-Id: <20190814165752.092367336@linuxfoundation.org>
In-Reply-To: <20190814165748.991235624@linuxfoundation.org>
References: <20190814165748.991235624@linuxfoundation.org>
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[ Upstream commit 5a46d3f71d5e5a9f82eabc682f996f1281705ac7 ]

Static analysis identified that index comparison against ITS entries in
iort_dev_find_its_id() is off by one.

Update the comparison condition and clarify the resulting error
message.

Fixes: 4bf2efd26d76 ("ACPI: Add new IORT functions to support MSI domain handling")
Link: https://lore.kernel.org/linux-arm-kernel/20190613065410.GB16334@mwanda/
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Will Deacon <will@kernel.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/arm64/iort.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 43c2615434b48..e11b5da6f828f 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -616,8 +616,8 @@ static int iort_dev_find_its_id(struct device *dev, u32 req_id,
 
 	/* Move to ITS specific data */
 	its = (struct acpi_iort_its_group *)node->node_data;
-	if (idx > its->its_count) {
-		dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n",
+	if (idx >= its->its_count) {
+		dev_err(dev, "requested ITS ID index [%d] overruns ITS entries [%d]\n",
 			idx, its->its_count);
 		return -ENXIO;
 	}
-- 
2.20.1