From: Greg KH <greg@kroah.com>
To: Johan Hovold <johan@kernel.org>
Cc: Oliver Neukum <oneukum@suse.de>,
Janne Kanniainen <janne.kanniainen@gmail.com>,
jkosina@suse.cz, cooloney@gmail.com,
linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
linux-usb@vger.kernel.org, linux-input@vger.kernel.org
Subject: Re: [PATCH v9] leds: USB: HID: Add support for MSI GT683R led panels
Date: Mon, 23 Jun 2014 12:17:23 -0400 [thread overview]
Message-ID: <20140623161723.GA20421@kroah.com> (raw)
In-Reply-To: <20140623144255.GA19911@localhost>
On Mon, Jun 23, 2014 at 04:42:55PM +0200, Johan Hovold wrote:
> On Mon, Jun 23, 2014 at 04:35:13PM +0200, Oliver Neukum wrote:
> > On Wed, 2014-06-18 at 19:05 +0300, Janne Kanniainen wrote:
> > > This driver adds support for USB controlled led panels that exists in
> > > MSI GT683R laptop
> > >
> >
> > > +static int gt683r_led_probe(struct hid_device *hdev,
> > > + const struct hid_device_id *id)
> > > +{
> > > + int i;
> > > + int ret;
> > > + int name_sz;
> > > + char *name;
> > > + struct gt683r_led *led;
> > > +
> > > + led = devm_kzalloc(&hdev->dev, sizeof(*led), GFP_KERNEL);
> > > + if (!led)
> > > + return -ENOMEM;
> > > +
> > > + led->mode = GT683R_LED_NORMAL;
> > > + led->hdev = hdev;
> > > + hid_set_drvdata(hdev, led);
> > > +
> > > + ret = hid_parse(hdev);
> > > + if (ret) {
> > > + hid_err(hdev, "hid parsing failed\n");
> > > + return ret;
> > > + }
> > > +
> > > + ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
> > > + if (ret) {
> > > + hid_err(hdev, "hw start failed\n");
> > > + return ret;
> > > + }
> > > +
> > > + for (i = 0; i < GT683R_LED_COUNT; i++) {
> > > + name_sz = strlen(dev_name(&hdev->dev)) +
> > > + strlen(gt683r_panel_names[i]) + 3;
> > > +
> > > + name = devm_kzalloc(&hdev->dev, name_sz, GFP_KERNEL);
> > > + if (!name) {
> > > + ret = -ENOMEM;
> > > + goto fail;
> > > + }
> > > +
> > > + snprintf(name, name_sz, "%s::%s",
> > > + dev_name(&hdev->dev), gt683r_panel_names[i]);
> > > + led->led_devs[i].name = name;
> > > + led->led_devs[i].max_brightness = 1;
> > > + led->led_devs[i].brightness_set = gt683r_brightness_set;
> > > + ret = led_classdev_register(&hdev->dev, &led->led_devs[i]);
> > > + if (ret) {
> > > + hid_err(hdev, "could not register led device\n");
> > > + goto fail;
> > > + }
> > > + }
> > > +
> > > + ret = device_create_file(&led->hdev->dev, &dev_attr_leds_mode);
> > > + if (ret) {
> > > + hid_err(hdev, "could not make mode attribute file\n");
> > > + goto fail;
> > > + }
> > > +
> >
> > This is the window.
> >
> > > + mutex_init(&led->lock);
> > > + INIT_WORK(&led->work, gt683r_led_work);
> > > +
> >
> > And here we have a problem. This is a race condition.
> > At this time you've already created the sysfs files. So
> > their methods can be called. They will lock a mutex and/or
> > schedule work that hasn't been initialized.
> > The initialization must be done before anything in sysfs
> > is created.
>
> Just move the initialisation of the lock and work to the other private
> data initialisations directly after it's allocated.
>
> Can you send a follow up patch, Janne?
No driver should be creating sysfs files directly, use the proper
attribute group interface instead. That way the files are created
_before_ the device is announced to userspace, instead of after, which
is a race condition there as well.
thanks,
greg k-h
next prev parent reply other threads:[~2014-06-23 16:17 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-05 21:29 [PATCH v2] leds: USB: Add support for MSI GT683R led panels Janne Kanniainen
2014-06-06 9:47 ` Johan Hovold
2014-06-07 10:12 ` Janne Kanniainen
2014-06-09 11:42 ` Johan Hovold
2014-06-10 21:10 ` Janne Kanniainen
2014-06-10 21:21 ` [PATCH v3] leds: USB: HID: " Janne Kanniainen
2014-06-11 11:25 ` Jiri Kosina
2014-06-11 14:06 ` Johan Hovold
2014-06-11 14:05 ` Johan Hovold
2014-06-11 15:30 ` Johan Hovold
2014-06-11 17:34 ` Johan Hovold
2014-06-11 22:48 ` [PATCH v4] " Janne Kanniainen
2014-06-12 9:06 ` Johan Hovold
2014-06-12 20:34 ` [PATCH v5] " Janne Kanniainen
2014-06-13 7:54 ` Johan Hovold
2014-06-13 17:19 ` Janne Kanniainen
2014-06-15 14:59 ` Janne Kanniainen
2014-06-16 7:39 ` Johan Hovold
2014-06-16 17:23 ` [PATCH v6] " Janne Kanniainen
2014-06-16 22:01 ` Janne Kanniainen
2014-06-17 13:46 ` Johan Hovold
2014-06-17 16:41 ` [PATCH v8] " Janne Kanniainen
2014-06-18 7:39 ` Johan Hovold
2014-06-18 16:05 ` [PATCH v9] " Janne Kanniainen
2014-06-18 16:11 ` Johan Hovold
2014-06-18 18:41 ` Janne Kanniainen
2014-06-18 18:46 ` Johan Hovold
2014-06-18 22:10 ` Jiri Kosina
2014-06-23 14:35 ` Oliver Neukum
2014-06-23 14:42 ` Johan Hovold
2014-06-23 16:17 ` Greg KH [this message]
2014-06-23 17:16 ` [PATCH v10] " Janne Kanniainen
2014-06-23 17:27 ` Johan Hovold
2014-06-23 18:23 ` Greg KH
2014-06-23 18:24 ` Greg KH
2014-06-23 19:31 ` Johan Hovold
2014-06-23 19:40 ` Greg KH
2014-06-23 19:52 ` Johan Hovold
2014-06-23 20:24 ` Greg KH
2014-06-23 20:44 ` Johan Hovold
2014-06-24 13:10 ` Bjørn Mork
2014-06-24 14:50 ` Johan Hovold
2014-06-24 19:38 ` [PATCH 1/2] HID: leds: fix race condition in MSI GT683R driver Janne Kanniainen
2014-06-24 19:38 ` [PATCH 2/2] HID: leds: move led_mode attribute to led-class devices " Janne Kanniainen
2014-06-24 19:56 ` Greg KH
2014-06-25 11:55 ` Johan Hovold
2014-06-25 15:59 ` [PATCH 2/2 v2] HID: leds: Use attribute-groups " Janne Kanniainen
2014-06-25 17:41 ` Johan Hovold
2014-06-25 18:13 ` [PATCH 2/2 v3] HID: leds: move led_mode attribute to led-class devices " Janne Kanniainen
2014-06-30 10:39 ` Johan Hovold
2014-07-01 17:50 ` [PATCH 2/2 v4] " Janne Kanniainen
2014-07-01 20:16 ` Johan Hovold
2014-07-02 17:37 ` [PATCH 2/2 v5] " Janne Kanniainen
2014-07-03 8:28 ` Johan Hovold
2014-07-03 17:17 ` [PATCH 1/2 v6] HID: gt683r: fix race condition Janne Kanniainen
2014-07-03 17:17 ` [PATCH 2/2 v6] HID: gt683r: move mode attribute to led-class devices Janne Kanniainen
2014-07-03 17:40 ` Johan Hovold
2014-07-03 18:17 ` Bryan Wu
2014-07-03 18:28 ` Janne Kanniainen
2014-07-03 17:34 ` [PATCH 1/2 v6] HID: gt683r: fix race condition Johan Hovold
2014-07-03 18:13 ` Bryan Wu
2014-06-25 19:09 ` [PATCH 2/2 v2] HID: leds: Use attribute-groups in MSI GT683R driver Jiri Kosina
2014-06-25 22:55 ` Bryan Wu
2014-06-30 10:47 ` Johan Hovold
2014-06-30 11:33 ` Jiri Kosina
2014-06-30 23:17 ` Bryan Wu
2014-07-01 8:48 ` Johan Hovold
2014-07-01 15:48 ` Bryan Wu
2014-07-01 17:53 ` Janne Kanniainen
2014-07-02 8:56 ` Jiri Kosina
2014-06-23 16:20 ` [PATCH v9] leds: USB: HID: Add support for MSI GT683R led panels Janne Kanniainen
2014-06-14 22:42 ` [PATCH v5] " Pavel Machek
2014-06-14 23:23 ` Janne Kanniainen
2014-06-16 7:45 ` Johan Hovold
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