* [PATCH] gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled
@ 2024-02-16 10:59 ` Bartosz Golaszewski
2024-02-16 12:35 ` Marek Szyprowski
0 siblings, 1 reply; 3+ messages in thread
From: Bartosz Golaszewski @ 2024-02-16 10:59 UTC (permalink / raw)
To: Bartosz Golaszewski, Kent Gibson, Linus Walleij,
Paul E . McKenney
Cc: linux-gpio, linux-kernel, Bartosz Golaszewski, Marek Szyprowski
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
We are actually passing the gc pointer to chip_dbg() so we have to
srcu_dereference() it.
Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/lkml/179caa10-5f86-4707-8bb0-fe1b316326d6@samsung.com/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
drivers/gpio/gpiolib-cdev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 85037fa4925e..f384fa278764 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2795,8 +2795,8 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
return ret;
guard(srcu)(&gdev->srcu);
-
- if (!rcu_access_pointer(gdev->chip))
+ gc = srcu_dereference(gdev->chip, &gdev->srcu);
+ if (!gc)
return -ENODEV;
chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
--
2.40.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled
2024-02-16 10:59 ` [PATCH] gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled Bartosz Golaszewski
@ 2024-02-16 12:35 ` Marek Szyprowski
2024-02-16 13:21 ` Bartosz Golaszewski
0 siblings, 1 reply; 3+ messages in thread
From: Marek Szyprowski @ 2024-02-16 12:35 UTC (permalink / raw)
To: Bartosz Golaszewski, Kent Gibson, Linus Walleij,
Paul E . McKenney
Cc: linux-gpio, linux-kernel, Bartosz Golaszewski
On 16.02.2024 11:59, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> We are actually passing the gc pointer to chip_dbg() so we have to
> srcu_dereference() it.
>
> Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Closes: https://lore.kernel.org/lkml/179caa10-5f86-4707-8bb0-fe1b316326d6@samsung.com/
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> drivers/gpio/gpiolib-cdev.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index 85037fa4925e..f384fa278764 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -2795,8 +2795,8 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
> return ret;
>
> guard(srcu)(&gdev->srcu);
> -
> - if (!rcu_access_pointer(gdev->chip))
> + gc = srcu_dereference(gdev->chip, &gdev->srcu);
> + if (!gc)
> return -ENODEV;
>
> chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled
2024-02-16 12:35 ` Marek Szyprowski
@ 2024-02-16 13:21 ` Bartosz Golaszewski
0 siblings, 0 replies; 3+ messages in thread
From: Bartosz Golaszewski @ 2024-02-16 13:21 UTC (permalink / raw)
To: Marek Szyprowski
Cc: Kent Gibson, Linus Walleij, Paul E . McKenney, linux-gpio,
linux-kernel, Bartosz Golaszewski
On Fri, Feb 16, 2024 at 1:35 PM Marek Szyprowski
<m.szyprowski@samsung.com> wrote:
>
> On 16.02.2024 11:59, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > We are actually passing the gc pointer to chip_dbg() so we have to
> > srcu_dereference() it.
> >
> > Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
> > Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Closes: https://lore.kernel.org/lkml/179caa10-5f86-4707-8bb0-fe1b316326d6@samsung.com/
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Thanks, patch applied.
Bart
[snip]
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-02-16 10:59 ` [PATCH] gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled Bartosz Golaszewski
2024-02-16 12:35 ` Marek Szyprowski
2024-02-16 13:21 ` Bartosz Golaszewski
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