Commit Graph

12 Commits

Author SHA1 Message Date
Johan Hovold
483d821108 gpio: sysfs: fix memory leaks and device hotplug
Unregister GPIOs requested through sysfs at chip remove to avoid leaking
the associated memory and sysfs entries.

The stale sysfs entries prevented the gpio numbers from being exported
when the gpio range was later reused (e.g. at device reconnect).

This also fixes the related module-reference leak.

Note that kernfs makes sure that any on-going sysfs operations finish
before the class devices are unregistered and that further accesses
fail.

The chip exported flag is used to prevent gpiod exports during removal.
This also makes it harder to trigger, but does not fix, the related race
between gpiochip_remove and export_store, which is really a race with
gpiod_request that needs to be addressed separately.

Also note that this would prevent the crashes (e.g. NULL-dereferences)
at reconnect that affects pre-3.18 kernels, as well as use-after-free on
operations on open attribute files on pre-3.14 kernels (prior to
kernfs).

Fixes: d8f388d8dc ("gpio: sysfs interface")
Cc: stable <stable@vger.kernel.org>	# v2.6.27: 01cca93a94
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-04-29 23:42:47 +02:00
Johan Hovold
49d2ca84e4 gpio: sysfs: fix memory leak in gpiod_sysfs_set_active_low
Fix memory leak in the gpio sysfs interface due to failure to drop
reference to device returned by class_find_device when setting the
gpio-line polarity.

Fixes: 0769746183 ("gpiolib: add support for changing value polarity
in sysfs")
Cc: stable <stable@vger.kernel.org>	# v2.6.33
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-30 10:29:33 +01:00
Johan Hovold
0f303db08d gpio: sysfs: fix memory leak in gpiod_export_link
Fix memory leak in the gpio sysfs interface due to failure to drop
reference to device returned by class_find_device when creating a link.

Fixes: a4177ee7f1 ("gpiolib: allow exported GPIO nodes to be named
using sysfs links")
Cc: stable <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-30 10:28:27 +01:00
Johan Hovold
ebbeba120a gpio: sysfs: fix gpio attribute-creation race
Fix attribute-creation race with userspace by using the default group
to create also the contingent gpio device attributes.

Fixes: d8f388d8dc ("gpio: sysfs interface")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15 17:20:56 +01:00
Johan Hovold
0915e6feb3 gpio: sysfs: fix gpio device-attribute leak
The gpio device attributes were never destroyed when the gpio was
unexported (or on export failures).

Use device_create_with_groups() to create the default device attributes
of the gpio class device. Note that this also fixes the
attribute-creation race with userspace for these attributes.

Remove contingent attributes in export error path and on unexport.

Fixes: d8f388d8dc ("gpio: sysfs interface")
Cc: stable <stable@vger.kernel.org>	# v2.6.27+
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15 17:20:15 +01:00
Johan Hovold
121b6a7995 gpio: sysfs: fix gpio-chip device-attribute leak
The gpio-chip device attributes were never destroyed when the device was
removed.

Fix by using device_create_with_groups() to create the device attributes
of the chip class device.

Note that this also fixes the attribute-creation race with userspace.

Fixes: d8f388d8dc ("gpio: sysfs interface")
Cc: stable <stable@vger.kernel.org>	# v2.6.27+
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-01-15 17:19:45 +01:00
Alexandre Courbot
8e53b0f190 gpio: remove const modifier from gpiod_get_direction()
Although gpiod_get_direction() can be considered side-effect free for
consumers, its internals involve setting or clearing bits in the
affected GPIO descriptor, for which we need to force-cast the const
descriptor variable to non-const. This could lead to incorrect behavior
if the compiler decides to optimize here, so remove this const
attribute. The intent is to make gpiod_get_direction() private anyway,
so it does not really matter.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-11-28 14:43:36 +01:00
Alexandre Courbot
e3a2e87893 gpio: rename gpio_lock_as_irq to gpiochip_lock_as_irq
This function actually operates on a gpio_chip, so its prefix should
reflect that fact for consistency with other functions defined in
gpio/driver.h.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-10-28 17:30:59 +01:00
Alexandre Courbot
7fd834ad77 gpio: remove useless check in gpiolib_sysfs_init()
An iterator variable cannot be NULL in its loop.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-24 16:03:45 +02:00
Alexandre Courbot
d74be6dfea gpio: remove gpiod_lock/unlock_as_irq()
gpio_lock/unlock_as_irq() are working with (chip, offset) arguments and
are thus not using the old integer namespace. Therefore, there is no
reason to have gpiod variants of these functions working with
descriptors, especially since the (chip, offset) tuple is more suitable
to the users of these functions (GPIO drivers, whereas GPIO descriptors
are targeted at GPIO consumers).

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-23 17:43:24 +02:00
Alexandre Courbot
14141a9352 gpio: simplify gpiochip_export()
For some reason gpiochip_export() would invalidate all the descriptors
of a chip if exporting it to sysfs failed. This does not appear as
necessary. Remove that part of the code.

While we are at it, add a note about the non-safety of temporarily
releasing a spinlock in the middle of the loop that protects its
iterator, and explain why this is done.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-23 17:37:51 +02:00
Alexandre Courbot
0eb4c6c267 gpio: move sysfs support to its own file
sysfs support is currently entangled within the core GPIO support, while
it should relly just be a (privileged) user of the integer GPIO API.
This patch is a first step towards making the gpiolib code more readable
by splitting it into logical parts.

Move all sysfs support to their own source file, and share static
members of gpiolib that need to be in the private gpiolib.h file. In
the future we will want to put some of them back into gpiolib.c, but this
first patch let us at least identify them.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-07-09 12:22:57 +02:00