From: Eduardo Valentin <eduval@amazon.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Eduardo Valentin <eduval@amazon.com>,
Jean Delvare <jdelvare@suse.com>, <linux-hwmon@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] hwmon: core: fix potential memory leak in *hwmon_device_register*
Date: Wed, 29 May 2019 16:14:45 -0700 [thread overview]
Message-ID: <20190529231445.GC18339@u40b0340c692b58f6553c.ant.amazon.com> (raw)
In-Reply-To: <20190528150640.GA5516@roeck-us.net>
On Tue, May 28, 2019 at 08:06:40AM -0700, Guenter Roeck wrote:
> Hi Eduardo,
>
> On Fri, May 17, 2019 at 04:13:37PM -0700, Eduardo Valentin wrote:
> > When registering a hwmon device with HWMON_C_REGISTER_TZ flag
> > in place, the hwmon subsystem will attempt to register the device
> > also with the thermal subsystem. When the of-thermal registration
> > fails, __hwmon_device_register jumps to ida_remove, leaving
> > the locally allocated hwdev pointer and also the hdev registered.
> >
> > This patch fixes both issues by jumping to a new label that
> > will first unregister hdev and the fall into the kfree of hwdev
> > to finally remove the idas and propagate the error code.
> >
> > Cc: Jean Delvare <jdelvare@suse.com>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: linux-hwmon@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Eduardo Valentin <eduval@amazon.com>
> > ---
> > drivers/hwmon/hwmon.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> > index 6b3559f58b67..6f1194952189 100644
> > --- a/drivers/hwmon/hwmon.c
> > +++ b/drivers/hwmon/hwmon.c
> > @@ -637,7 +637,7 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
> > hwdev, j);
> > if (err) {
> > device_unregister(hdev);
> > - goto ida_remove;
> > + goto device_unregister;
>
> Good find, but device_unregister() is already called above.
> You need to either remove that, or replace the goto to point to free_hwmon.
> The new label would probably the cleaner solution since it follows the
> coding style.
Right, somehow I completely missed that unregister call. In any case, I will
take the route of adding a new label and remove the unregister call above.
>
> Thanks
> Guenter
>
> > }
> > }
> > }
> > @@ -646,6 +646,8 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
> >
> > return hdev;
> >
> > +device_unregister:
> > + device_unregister(hdev);
> > free_hwmon:
> > kfree(hwdev);
> > ida_remove:
> > --
> > 2.21.0
> >
--
All the best,
Eduardo Valentin
prev parent reply other threads:[~2019-05-29 23:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190517231337.27859-1-eduval@amazon.com>
2019-05-17 23:13 ` [PATCH 1/2] hwmon: core: add thermal sensors only if dev->of_node is present Eduardo Valentin
2019-05-28 15:08 ` Guenter Roeck
2019-05-29 23:12 ` Eduardo Valentin
2019-05-17 23:13 ` [PATCH 2/2] hwmon: core: fix potential memory leak in *hwmon_device_register* Eduardo Valentin
2019-05-28 15:06 ` Guenter Roeck
2019-05-29 23:14 ` Eduardo Valentin [this message]
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