linux-kernel - [PATCH] opp: fix memory leak in _allocate_opp

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Date:   Thu, 24 Dec 2020 18:49:27 +0800
From:   quanyang.wang@...driver.com
To:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        Stephan Gerhold <stephan@...hold.net>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Quanyang Wang <quanyang.wang@...driver.com>
Subject: [PATCH] opp: fix memory leak in _allocate_opp_table

From: Quanyang Wang <quanyang.wang@...driver.com>

In function _allocate_opp_table, opp_dev is allocated and referenced
by opp_table via _add_opp_dev. But in the case that the subsequent calls
return -EPROBE_DEFER, it will jump to err label and opp_table will be
freed. Then opp_dev becomes an unreferenced object to cause memory leak.
So let's call _remove_opp_dev to do the cleanup.

This fixes the following kmemleak report:

unreferenced object 0xffff000801524a00 (size 128):
  comm "swapper/0", pid 1, jiffies 4294892465 (age 84.616s)
  hex dump (first 32 bytes):
    40 00 56 01 08 00 ff ff 40 00 56 01 08 00 ff ff  @.V.....@.......
    b8 52 77 7f 08 00 ff ff 00 3c 4c 00 08 00 ff ff  .Rw......<L.....
  backtrace:
    [<00000000b1289fb1>] kmemleak_alloc+0x30/0x40
    [<0000000056da48f0>] kmem_cache_alloc+0x3d4/0x588
    [<00000000a84b3b0e>] _add_opp_dev+0x2c/0x88
    [<0000000062a380cd>] _add_opp_table_indexed+0x124/0x268
    [<000000008b4c8f1f>] dev_pm_opp_of_add_table+0x20/0x1d8
    [<00000000e5316798>] dev_pm_opp_of_cpumask_add_table+0x48/0xf0
    [<00000000db0a8ec2>] dt_cpufreq_probe+0x20c/0x448
    [<0000000030a3a26c>] platform_probe+0x68/0xd8
    [<00000000c618e78d>] really_probe+0xd0/0x3a0
    [<00000000642e856f>] driver_probe_device+0x58/0xb8
    [<00000000f10f5307>] device_driver_attach+0x74/0x80
    [<0000000004f254b8>] __driver_attach+0x58/0xe0
    [<0000000009d5d19e>] bus_for_each_dev+0x70/0xc8
    [<0000000000d22e1c>] driver_attach+0x24/0x30
    [<0000000001d4e952>] bus_add_driver+0x14c/0x1f0
    [<0000000089928aaa>] driver_register+0x64/0x120

Fixes: dd461cd9183f ("opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER")
Signed-off-by: Quanyang Wang <quanyang.wang@...driver.com>
---
 drivers/opp/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 4268eb359915..c9e50836b4c2 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1092,7 +1092,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 	if (IS_ERR(opp_table->clk)) {
 		ret = PTR_ERR(opp_table->clk);
 		if (ret == -EPROBE_DEFER)
-			goto err;
+			goto remove_opp_dev;
 
 		dev_dbg(dev, "%s: Couldn't find clock: %d\n", __func__, ret);
 	}
@@ -1101,7 +1101,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 	ret = dev_pm_opp_of_find_icc_paths(dev, opp_table);
 	if (ret) {
 		if (ret == -EPROBE_DEFER)
-			goto err;
+			goto remove_opp_dev;
 
 		dev_warn(dev, "%s: Error finding interconnect paths: %d\n",
 			 __func__, ret);
@@ -1113,6 +1113,8 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 
 	return opp_table;
 
+remove_opp_dev:
+	_remove_opp_dev(opp_dev, opp_table);
 err:
 	kfree(opp_table);
 	return ERR_PTR(ret);
-- 
2.25.1