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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, Dan Carpenter <dan.carpenter@oracle.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 042/310] PowerCap: Fix an error code in powercap_register_zone()
Date:   Wed, 11 Apr 2018 20:33:01 +0200
Message-Id: <20180411183624.080219352@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>


[ Upstream commit 216c4e9db4c9d1d2a382b42880442dc632cd47d9 ]

In the current code we accidentally return the successful result from
idr_alloc() instead of a negative error pointer.  The caller is looking
for an error pointer and so it treats the returned value as a valid
pointer.

This one might be a bit serious because if it lets people get around the
kernel's protection for remapping NULL.  I'm not sure.

Fixes: 75d2364ea0ca (PowerCap: Add class driver)
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/powercap/powercap_sys.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/powercap/powercap_sys.c
+++ b/drivers/powercap/powercap_sys.c
@@ -538,6 +538,7 @@ struct powercap_zone *powercap_register_
 
 	power_zone->id = result;
 	idr_init(&power_zone->idr);
+	result = -ENOMEM;
 	power_zone->name = kstrdup(name, GFP_KERNEL);
 	if (!power_zone->name)
 		goto err_name_alloc;