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>,
stable@vger.kernel.org
Subject: [PATCH 2/2] gpio: fix gpio-device list corruption
Date: Fri, 26 Feb 2021 15:52:46 +0100 [thread overview]
Message-ID: <20210226145246.1171-3-johan@kernel.org> (raw)
In-Reply-To: <20210226145246.1171-1-johan@kernel.org>
Make sure to hold the gpio_lock when removing the gpio device from the
gpio_devices list (when dropping the last reference) to avoid corrupting
the list when there are concurrent accesses.
Fixes: ff2b13592299 ("gpio: make the gpiochip a real device")
Cc: stable@vger.kernel.org # 4.6
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e1016bc8cf14..42bdc55a15f9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -475,8 +475,12 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
static void gpiodevice_release(struct device *dev)
{
struct gpio_device *gdev = container_of(dev, struct gpio_device, dev);
+ unsigned long flags;
+ spin_lock_irqsave(&gpio_lock, flags);
list_del(&gdev->list);
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
ida_free(&gpio_ida, gdev->id);
kfree_const(gdev->label);
kfree(gdev->descs);
--
2.26.2
next prev parent reply other threads:[~2021-02-26 14:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 14:52 [PATCH 0/2] gpio: regression fixes Johan Hovold
2021-02-26 14:52 ` [PATCH 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
2021-02-26 21:54 ` Saravana Kannan
2021-03-01 8:44 ` Johan Hovold
2021-02-26 14:52 ` Johan Hovold [this message]
2021-02-26 20:59 ` [PATCH 2/2] gpio: fix gpio-device list corruption Saravana Kannan
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