* [PATCH v2 0/2] gpio: regression fixes
@ 2021-03-01 9:05 Johan Hovold
2021-03-01 9:05 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Johan Hovold @ 2021-03-01 9:05 UTC (permalink / raw)
To: Linus Walleij, Bartosz Golaszewski
Cc: Greg Kroah-Hartman, Saravana Kannan, linux-gpio, linux-kernel,
Johan Hovold
Here's a fix for a regression in 5.12 due to the new stub-driver hack,
and a fix for potential list corruption due to missing locking which has
been there since the introduction of the character-device interface in
4.6.
Johan
Changes in v2
- drop the corresponding drv_set_drvdata() which is no longer needed
after patch 1/2
- add Saravanas's reviewed-by tag to patch 2/2
Johan Hovold (2):
gpio: fix NULL-deref-on-deregistration regression
gpio: fix gpio-device list corruption
drivers/gpio/gpiolib.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--
2.26.2
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression
2021-03-01 9:05 [PATCH v2 0/2] gpio: regression fixes Johan Hovold
@ 2021-03-01 9:05 ` Johan Hovold
2021-03-02 15:40 ` Linus Walleij
2021-03-01 9:05 ` [PATCH v2 2/2] gpio: fix gpio-device list corruption Johan Hovold
2021-03-01 9:12 ` [PATCH v2 0/2] gpio: regression fixes Bartosz Golaszewski
2 siblings, 1 reply; 9+ messages in thread
From: Johan Hovold @ 2021-03-01 9:05 UTC (permalink / raw)
To: Linus Walleij, Bartosz Golaszewski
Cc: Greg Kroah-Hartman, Saravana Kannan, linux-gpio, linux-kernel,
Johan Hovold, syzbot+d27b4c8adbbff70fbfde
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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v2 2/2] gpio: fix gpio-device list corruption
2021-03-01 9:05 [PATCH v2 0/2] gpio: regression fixes Johan Hovold
2021-03-01 9:05 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
@ 2021-03-01 9:05 ` Johan Hovold
2021-03-02 15:41 ` Linus Walleij
2021-03-01 9:12 ` [PATCH v2 0/2] gpio: regression fixes Bartosz Golaszewski
2 siblings, 1 reply; 9+ messages in thread
From: Johan Hovold @ 2021-03-01 9:05 UTC (permalink / raw)
To: Linus Walleij, Bartosz Golaszewski
Cc: Greg Kroah-Hartman, Saravana Kannan, linux-gpio, linux-kernel,
Johan Hovold, stable
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
Reviewed-by: Saravana Kannan <saravanak@google.com>
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 6e0572515d02..4253837f870b 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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v2 0/2] gpio: regression fixes
2021-03-01 9:05 [PATCH v2 0/2] gpio: regression fixes Johan Hovold
2021-03-01 9:05 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
2021-03-01 9:05 ` [PATCH v2 2/2] gpio: fix gpio-device list corruption Johan Hovold
@ 2021-03-01 9:12 ` Bartosz Golaszewski
2021-03-01 16:57 ` Andy Shevchenko
2021-03-01 17:07 ` Saravana Kannan
2 siblings, 2 replies; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-03-01 9:12 UTC (permalink / raw)
To: Johan Hovold
Cc: Linus Walleij, Greg Kroah-Hartman, Saravana Kannan, linux-gpio, LKML
On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
>
> Here's a fix for a regression in 5.12 due to the new stub-driver hack,
> and a fix for potential list corruption due to missing locking which has
> been there since the introduction of the character-device interface in
> 4.6.
>
> Johan
>
> Changes in v2
> - drop the corresponding drv_set_drvdata() which is no longer needed
> after patch 1/2
> - add Saravanas's reviewed-by tag to patch 2/2
>
>
> Johan Hovold (2):
> gpio: fix NULL-deref-on-deregistration regression
> gpio: fix gpio-device list corruption
>
> drivers/gpio/gpiolib.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> --
> 2.26.2
>
Patches applied, thanks!
Bartosz
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 0/2] gpio: regression fixes
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
1 sibling, 1 reply; 9+ messages in thread
From: Andy Shevchenko @ 2021-03-01 16:57 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Johan Hovold, Linus Walleij, Greg Kroah-Hartman, Saravana Kannan,
linux-gpio, LKML
On Mon, Mar 1, 2021 at 11:13 AM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:
> On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
> >
> > Here's a fix for a regression in 5.12 due to the new stub-driver hack,
> > and a fix for potential list corruption due to missing locking which has
> > been there since the introduction of the character-device interface in
> > 4.6.
> >
> > Johan
> >
> > Changes in v2
> > - drop the corresponding drv_set_drvdata() which is no longer needed
> > after patch 1/2
> > - add Saravanas's reviewed-by tag to patch 2/2
> >
> >
> > Johan Hovold (2):
> > gpio: fix NULL-deref-on-deregistration regression
> > gpio: fix gpio-device list corruption
> >
> > drivers/gpio/gpiolib.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> Patches applied, thanks!
Ooops, you are fast!
Anyway, I have tested with gpio-aggregator (w/o this series it
sparkles with all possible bugs).
Tested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 0/2] gpio: regression fixes
2021-03-01 9:12 ` [PATCH v2 0/2] gpio: regression fixes Bartosz Golaszewski
2021-03-01 16:57 ` Andy Shevchenko
@ 2021-03-01 17:07 ` Saravana Kannan
1 sibling, 0 replies; 9+ messages in thread
From: Saravana Kannan @ 2021-03-01 17:07 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Johan Hovold, Linus Walleij, Greg Kroah-Hartman, linux-gpio, LKML
On Mon, Mar 1, 2021 at 1:12 AM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:
>
> On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
> >
> > Here's a fix for a regression in 5.12 due to the new stub-driver hack,
> > and a fix for potential list corruption due to missing locking which has
> > been there since the introduction of the character-device interface in
> > 4.6.
> >
> > Johan
> >
> > Changes in v2
> > - drop the corresponding drv_set_drvdata() which is no longer needed
> > after patch 1/2
> > - add Saravanas's reviewed-by tag to patch 2/2
> >
> >
> > Johan Hovold (2):
> > gpio: fix NULL-deref-on-deregistration regression
> > gpio: fix gpio-device list corruption
> >
> > drivers/gpio/gpiolib.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > --
> > 2.26.2
> >
>
> Patches applied, thanks!
Thanks Johan and Bartosz!
-Saravana
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 0/2] gpio: regression fixes
2021-03-01 16:57 ` Andy Shevchenko
@ 2021-03-01 18:38 ` Bartosz Golaszewski
0 siblings, 0 replies; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-03-01 18:38 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Johan Hovold, Linus Walleij, Greg Kroah-Hartman, Saravana Kannan,
linux-gpio, LKML
On Mon, Mar 1, 2021 at 5:57 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, Mar 1, 2021 at 11:13 AM Bartosz Golaszewski
> <bgolaszewski@baylibre.com> wrote:
> > On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
> > >
> > > Here's a fix for a regression in 5.12 due to the new stub-driver hack,
> > > and a fix for potential list corruption due to missing locking which has
> > > been there since the introduction of the character-device interface in
> > > 4.6.
> > >
> > > Johan
> > >
> > > Changes in v2
> > > - drop the corresponding drv_set_drvdata() which is no longer needed
> > > after patch 1/2
> > > - add Saravanas's reviewed-by tag to patch 2/2
> > >
> > >
> > > Johan Hovold (2):
> > > gpio: fix NULL-deref-on-deregistration regression
> > > gpio: fix gpio-device list corruption
> > >
> > > drivers/gpio/gpiolib.c | 7 +++++--
> > > 1 file changed, 5 insertions(+), 2 deletions(-)
>
> > Patches applied, thanks!
>
> Ooops, you are fast!
The regression broke my gpip-sim I'm working on right now so I tested it too.
Bartosz
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression
2021-03-01 9:05 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
@ 2021-03-02 15:40 ` Linus Walleij
0 siblings, 0 replies; 9+ messages in thread
From: Linus Walleij @ 2021-03-02 15:40 UTC (permalink / raw)
To: Johan Hovold
Cc: Bartosz Golaszewski, Greg Kroah-Hartman, Saravana Kannan,
open list:GPIO SUBSYSTEM, linux-kernel,
syzbot+d27b4c8adbbff70fbfde
On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
> 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>
Oh nice catch!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] gpio: fix gpio-device list corruption
2021-03-01 9:05 ` [PATCH v2 2/2] gpio: fix gpio-device list corruption Johan Hovold
@ 2021-03-02 15:41 ` Linus Walleij
0 siblings, 0 replies; 9+ messages in thread
From: Linus Walleij @ 2021-03-02 15:41 UTC (permalink / raw)
To: Johan Hovold
Cc: Bartosz Golaszewski, Greg Kroah-Hartman, Saravana Kannan,
open list:GPIO SUBSYSTEM, linux-kernel, stable
On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> wrote:
> 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
> Reviewed-by: Saravana Kannan <saravanak@google.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>
Excellent fix as well,
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-03-02 21:24 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-01 9:05 [PATCH v2 0/2] gpio: regression fixes Johan Hovold
2021-03-01 9:05 ` [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Johan Hovold
2021-03-02 15:40 ` 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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