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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, Shawn Guo <shawn.guo@linaro.org>,
        Erik Kaneda <erik.kaneda@intel.com>,
        Bob Moore <robert.moore@intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 122/348] ACPICA: Fix memory leak caused by _CID repair function
Date:   Mon, 12 Jul 2021 08:08:26 +0200
Message-Id: <20210712060717.605552933@linuxfoundation.org>
In-Reply-To: <20210712060659.886176320@linuxfoundation.org>
References: <20210712060659.886176320@linuxfoundation.org>
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From: Erik Kaneda <erik.kaneda@intel.com>

[ Upstream commit c27bac0314131b11bccd735f7e8415ac6444b667 ]

ACPICA commit 180cb53963aa876c782a6f52cc155d951b26051a

According to the ACPI spec, _CID returns a package containing
hardware ID's. Each element of an ASL package contains a reference
count from the parent package as well as the element itself.

Name (TEST, Package() {
    "String object" // this package element has a reference count of 2
})

A memory leak was caused in the _CID repair function because it did
not decrement the reference count created by the package. Fix the
memory leak by calling acpi_ut_remove_reference on _CID package elements
that represent a hardware ID (_HID).

Link: https://github.com/acpica/acpica/commit/180cb539
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/acpi/acpica/nsrepair2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/acpi/acpica/nsrepair2.c b/drivers/acpi/acpica/nsrepair2.c
index 663d85e0adba..b7c408ce340c 100644
--- a/drivers/acpi/acpica/nsrepair2.c
+++ b/drivers/acpi/acpica/nsrepair2.c
@@ -375,6 +375,13 @@ acpi_ns_repair_CID(struct acpi_evaluate_info *info,
 
 			(*element_ptr)->common.reference_count =
 			    original_ref_count;
+
+			/*
+			 * The original_element holds a reference from the package object
+			 * that represents _HID. Since a new element was created by _HID,
+			 * remove the reference from the _CID package.
+			 */
+			acpi_ut_remove_reference(original_element);
 		}
 
 		element_ptr++;
-- 
2.30.2