From: Johan Hovold <johan@kernel.org>
To: Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Saravana Kannan <saravanak@google.com>,
linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Johan Hovold <johan@kernel.org>,
syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com
Subject: [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression
Date: Mon, 1 Mar 2021 10:05:18 +0100 [thread overview]
Message-ID: <20210301090519.26192-2-johan@kernel.org> (raw)
In-Reply-To: <20210301090519.26192-1-johan@kernel.org>
Fix a NULL-pointer deference when deregistering the gpio character
device that was introduced by the recent stub-driver hack. When the new
"driver" is unbound as part of deregistration, driver core clears the
driver-data pointer which is used to retrieve the struct gpio_device in
its release callback.
Fix this by using container_of() in the release callback as should have
been done all along.
Fixes: 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default")
Cc: Saravana Kannan <saravanak@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reported-by: syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index adf55db080d8..6e0572515d02 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -474,7 +474,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
static void gpiodevice_release(struct device *dev)
{
- struct gpio_device *gdev = dev_get_drvdata(dev);
+ struct gpio_device *gdev = container_of(dev, struct gpio_device, dev);
list_del(&gdev->list);
ida_free(&gpio_ida, gdev->id);
@@ -605,7 +605,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
goto err_free_ida;
device_initialize(&gdev->dev);
- dev_set_drvdata(&gdev->dev, gdev);
if (gc->parent && gc->parent->driver)
gdev->owner = gc->parent->driver->owner;
else if (gc->owner)
--
2.26.2
next prev parent reply other threads:[~2021-03-01 9:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 9:05 [PATCH v2 0/2] gpio: regression fixes Johan Hovold
2021-03-01 9:05 ` Johan Hovold [this message]
2021-03-02 15:40 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Linus Walleij
2021-03-01 9:05 ` [PATCH v2 2/2] gpio: fix gpio-device list corruption Johan Hovold
2021-03-02 15:41 ` Linus Walleij
2021-03-01 9:12 ` [PATCH v2 0/2] gpio: regression fixes Bartosz Golaszewski
2021-03-01 16:57 ` Andy Shevchenko
2021-03-01 18:38 ` Bartosz Golaszewski
2021-03-01 17:07 ` Saravana Kannan
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