linux-kernel - [PATCH] cpufreq: ti-cpufreq: Fix couple of minor issues in probe()

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Date:   Mon, 26 Mar 2018 16:52:44 -0500
From:   Suman Anna <s-anna@...com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
CC:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Dave Gerlach <d-gerlach@...com>, Tero Kristo <t-kristo@...com>,
        <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Suman Anna <s-anna@...com>, Zumeng Chen <zumeng.chen@...il.com>
Subject: [PATCH] cpufreq: ti-cpufreq: Fix couple of minor issues in probe()

Commit 05829d9431df ("cpufreq: ti-cpufreq: kfree opp_data when
failure") has fixed a memory leak in the failure path, however
kmemleak still keeps reporting a leak even on successful probes.
This is a false-positive and is mostly a result of the opp_data
variable not being stored anywhere in the probe function. The
patch also returned a positive value on the get_cpu_device()
failure instead of a negative value.

unreferenced object 0xecae4d80 (size 64):
  comm "swapper/0", pid 1, jiffies 4294937673 (age 154.420s)
  hex dump (first 32 bytes):
    10 40 d9 ee 74 b7 db ee 00 24 ac ec 20 a3 ea c0  .@.......$.. ...
    00 26 ac ec 00 00 00 00 00 00 00 00 00 00 00 00  .&..............
  backtrace:
    [<ec080d62>] platform_drv_probe+0x50/0xac
    [<cbde8566>] driver_probe_device+0x24c/0x330
    [<a5818eb4>] bus_for_each_drv+0x54/0xb8
    [<2c6f7021>] __device_attach+0xcc/0x13c
    [<a04478a2>] bus_probe_device+0x88/0x90
    [<b322c963>] device_add+0x38c/0x5b4
    [<6f1af99b>] platform_device_add+0x100/0x220
    [<cef42bca>] platform_device_register_full+0xf0/0x104
    [<4d492439>] ti_cpufreq_init+0x44/0x6c
    [<81222e89>] do_one_initcall+0x48/0x190
    [<3bebf42a>] kernel_init_freeable+0x1f4/0x2b8
    [<230ad7df>] kernel_init+0x8/0x110
    [<43a165c3>] ret_from_fork+0x14/0x20
    [<  (null)>]   (null)
    [<87288797>] 0xffffffff

Fix both issues by replacing the previous logic by using the devres
managed API for allocating the opp_data variable, and simplifying
the get_cpu_device() failure return path.

Fixes: 05829d9431df ("cpufreq: ti-cpufreq: kfree opp_data when failure")
Cc: Zumeng Chen <zumeng.chen@...il.com>
Signed-off-by: Suman Anna <s-anna@...com>
---
 drivers/cpufreq/ti-cpufreq.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/ti-cpufreq.c b/drivers/cpufreq/ti-cpufreq.c
index a099b7bf74cd..7d353a21935b 100644
--- a/drivers/cpufreq/ti-cpufreq.c
+++ b/drivers/cpufreq/ti-cpufreq.c
@@ -217,7 +217,7 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
 	if (!match)
 		return -ENODEV;
 
-	opp_data = kzalloc(sizeof(*opp_data), GFP_KERNEL);
+	opp_data = devm_kzalloc(&pdev->dev, sizeof(*opp_data), GFP_KERNEL);
 	if (!opp_data)
 		return -ENOMEM;
 
@@ -226,8 +226,7 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
 	opp_data->cpu_dev = get_cpu_device(0);
 	if (!opp_data->cpu_dev) {
 		pr_err("%s: Failed to get device for CPU0\n", __func__);
-		ret = ENODEV;
-		goto free_opp_data;
+		return -ENODEV;
 	}
 
 	opp_data->opp_node = dev_pm_opp_of_get_opp_desc_node(opp_data->cpu_dev);
@@ -285,8 +284,6 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
 
 fail_put_node:
 	of_node_put(opp_data->opp_node);
-free_opp_data:
-	kfree(opp_data);
 
 	return ret;
 }
-- 
2.16.2