* [PATCH 1/2] gpiolib: Fix NULL pointer deference
@ 2016-06-03 17:10 Ricardo Ribalda Delgado
2016-06-03 17:10 ` [PATCH 2/2] gpiolib: Fix unaligned used of reference counters Ricardo Ribalda Delgado
2016-06-08 8:39 ` [PATCH 1/2] gpiolib: Fix NULL pointer deference Linus Walleij
0 siblings, 2 replies; 5+ messages in thread
From: Ricardo Ribalda Delgado @ 2016-06-03 17:10 UTC (permalink / raw)
To: Linus Walleij, Alexandre Courbot, linux-gpio, linux-kernel
Cc: Ricardo Ribalda Delgado
Under some circumstances, a gpiochip might be half cleaned from the
gpio_device list.
This patch makes sure that the chip pointer is still valid, before
calling the match function.
[ 104.088296] BUG: unable to handle kernel NULL pointer dereference at
0000000000000090
[ 104.089772] IP: [<ffffffff813d2045>] of_gpiochip_find_and_xlate+0x15/0x80
[ 104.128273] Call Trace:
[ 104.129802] [<ffffffff813d2030>] ? of_parse_own_gpio+0x1f0/0x1f0
[ 104.131353] [<ffffffff813cd910>] gpiochip_find+0x60/0x90
[ 104.132868] [<ffffffff813d21ba>] of_get_named_gpiod_flags+0x9a/0x120
...
[ 104.141586] [<ffffffff8163d12b>] gpio_led_probe+0x11b/0x360
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
We might want to cc: stable on these two patches
drivers/gpio/gpiolib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index d407f904a31c..0626cc96744b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -858,7 +858,7 @@ struct gpio_chip *gpiochip_find(void *data,
spin_lock_irqsave(&gpio_lock, flags);
list_for_each_entry(gdev, &gpio_devices, list)
- if (match(gdev->chip, data))
+ if (gdev->chip && match(gdev->chip, data))
break;
/* No match? */
--
2.8.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] gpiolib: Fix unaligned used of reference counters
2016-06-03 17:10 [PATCH 1/2] gpiolib: Fix NULL pointer deference Ricardo Ribalda Delgado
@ 2016-06-03 17:10 ` Ricardo Ribalda Delgado
2016-06-08 8:41 ` Linus Walleij
2016-06-08 8:39 ` [PATCH 1/2] gpiolib: Fix NULL pointer deference Linus Walleij
1 sibling, 1 reply; 5+ messages in thread
From: Ricardo Ribalda Delgado @ 2016-06-03 17:10 UTC (permalink / raw)
To: Linus Walleij, Alexandre Courbot, linux-gpio, linux-kernel
Cc: Ricardo Ribalda Delgado
gpiolib relies on the reference counters to clean up the gpio_device
structure.
Although the number of get/put is properly aligned on gpiolib.c
itself, it does not take into consideration how the referece counters
are affected by other external functions such as cdev_add and device_add.
Because of this, after the last call to put_device, the reference counter
has a value of +3, therefore never calling gpiodevice_release.
Due to the fact that some of the device has already been cleaned on
gpiochip_remove, the library will end up OOPsing the kernel (e.g. a call
to of_gpiochip_find_and_xlate).
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
We might want to cc: stable on these two patches
drivers/gpio/gpiolib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 0626cc96744b..d829f2127524 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -438,7 +438,6 @@ static void gpiodevice_release(struct device *dev)
{
struct gpio_device *gdev = dev_get_drvdata(dev);
- cdev_del(&gdev->chrdev);
list_del(&gdev->list);
ida_simple_remove(&gpio_ida, gdev->id);
kfree(gdev->label);
@@ -471,7 +470,6 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)
/* From this point, the .release() function cleans up gpio_device */
gdev->dev.release = gpiodevice_release;
- get_device(&gdev->dev);
pr_debug("%s: registered GPIOs %d to %d on device: %s (%s)\n",
__func__, gdev->base, gdev->base + gdev->ngpio - 1,
dev_name(&gdev->dev), gdev->chip->label ? : "generic");
@@ -759,6 +757,8 @@ void gpiochip_remove(struct gpio_chip *chip)
* be removed, else it will be dangling until the last user is
* gone.
*/
+ cdev_del(&gdev->chrdev);
+ device_del(&gdev->dev);
put_device(&gdev->dev);
}
EXPORT_SYMBOL_GPL(gpiochip_remove);
--
2.8.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] gpiolib: Fix unaligned used of reference counters
2016-06-03 17:10 ` [PATCH 2/2] gpiolib: Fix unaligned used of reference counters Ricardo Ribalda Delgado
@ 2016-06-08 8:41 ` Linus Walleij
0 siblings, 0 replies; 5+ messages in thread
From: Linus Walleij @ 2016-06-08 8:41 UTC (permalink / raw)
To: Ricardo Ribalda Delgado, Grygorii Strashko, Roger Quadros
Cc: Alexandre Courbot, linux-gpio, linux-kernel
On Fri, Jun 3, 2016 at 7:10 PM, Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:
> gpiolib relies on the reference counters to clean up the gpio_device
> structure.
>
> Although the number of get/put is properly aligned on gpiolib.c
> itself, it does not take into consideration how the referece counters
> are affected by other external functions such as cdev_add and device_add.
>
> Because of this, after the last call to put_device, the reference counter
> has a value of +3, therefore never calling gpiodevice_release.
>
> Due to the fact that some of the device has already been cleaned on
> gpiochip_remove, the library will end up OOPsing the kernel (e.g. a call
> to of_gpiochip_find_and_xlate).
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Again, thanks for fixing my stupid mistakes.
Applied and tagged for stable.
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] gpiolib: Fix NULL pointer deference
2016-06-03 17:10 [PATCH 1/2] gpiolib: Fix NULL pointer deference Ricardo Ribalda Delgado
2016-06-03 17:10 ` [PATCH 2/2] gpiolib: Fix unaligned used of reference counters Ricardo Ribalda Delgado
@ 2016-06-08 8:39 ` Linus Walleij
2016-06-08 9:46 ` Grygorii Strashko
1 sibling, 1 reply; 5+ messages in thread
From: Linus Walleij @ 2016-06-08 8:39 UTC (permalink / raw)
To: Ricardo Ribalda Delgado, Grygorii Strashko, Roger Quadros
Cc: Alexandre Courbot, linux-gpio, linux-kernel
On Fri, Jun 3, 2016 at 7:10 PM, Ricardo Ribalda Delgado
<ricardo.ribalda@gmail.com> wrote:
> Under some circumstances, a gpiochip might be half cleaned from the
> gpio_device list.
>
> This patch makes sure that the chip pointer is still valid, before
> calling the match function.
>
> [ 104.088296] BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000090
> [ 104.089772] IP: [<ffffffff813d2045>] of_gpiochip_find_and_xlate+0x15/0x80
> [ 104.128273] Call Trace:
> [ 104.129802] [<ffffffff813d2030>] ? of_parse_own_gpio+0x1f0/0x1f0
> [ 104.131353] [<ffffffff813cd910>] gpiochip_find+0x60/0x90
> [ 104.132868] [<ffffffff813d21ba>] of_get_named_gpiod_flags+0x9a/0x120
> ...
> [ 104.141586] [<ffffffff8163d12b>] gpio_led_probe+0x11b/0x360
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Oh there is the fix that Roger and Grygorii needs.
Applied to fixes and tagged for stable.
Sorry for screwing things up :(
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] gpiolib: Fix NULL pointer deference
2016-06-08 8:39 ` [PATCH 1/2] gpiolib: Fix NULL pointer deference Linus Walleij
@ 2016-06-08 9:46 ` Grygorii Strashko
0 siblings, 0 replies; 5+ messages in thread
From: Grygorii Strashko @ 2016-06-08 9:46 UTC (permalink / raw)
To: Linus Walleij, Ricardo Ribalda Delgado, Roger Quadros
Cc: Alexandre Courbot, linux-gpio, linux-kernel
On 06/08/2016 11:39 AM, Linus Walleij wrote:
> On Fri, Jun 3, 2016 at 7:10 PM, Ricardo Ribalda Delgado
> <ricardo.ribalda@gmail.com> wrote:
>
>> Under some circumstances, a gpiochip might be half cleaned from the
>> gpio_device list.
>>
>> This patch makes sure that the chip pointer is still valid, before
>> calling the match function.
>>
>> [ 104.088296] BUG: unable to handle kernel NULL pointer dereference at
>> 0000000000000090
>> [ 104.089772] IP: [<ffffffff813d2045>] of_gpiochip_find_and_xlate+0x15/0x80
>> [ 104.128273] Call Trace:
>> [ 104.129802] [<ffffffff813d2030>] ? of_parse_own_gpio+0x1f0/0x1f0
>> [ 104.131353] [<ffffffff813cd910>] gpiochip_find+0x60/0x90
>> [ 104.132868] [<ffffffff813d21ba>] of_get_named_gpiod_flags+0x9a/0x120
>> ...
>> [ 104.141586] [<ffffffff8163d12b>] gpio_led_probe+0x11b/0x360
>>
>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
>
> Oh there is the fix that Roger and Grygorii needs.
>
> Applied to fixes and tagged for stable.
>
> Sorry for screwing things up :(
>
Np. :)
--
regards,
-grygorii
^ permalink raw reply [flat|nested] 5+ messages in thread
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2016-06-03 17:10 [PATCH 1/2] gpiolib: Fix NULL pointer deference Ricardo Ribalda Delgado
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2016-06-08 8:41 ` Linus Walleij
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