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* [PATCH] gpiolib: fix filtering out unwanted events
@ 2017-06-23 11:45 Bartosz Golaszewski
  2017-06-23 11:45 ` Bartosz Golaszewski
  2017-06-23 14:09 ` Bartosz Golaszewski
  0 siblings, 2 replies; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-06-23 11:45 UTC (permalink / raw)
  To: Linus Walleij; +Cc: linux-gpio, linux-kernel, Bartosz Golaszewski

Hi Linux,

I've just fixed an issue in libgpiod which accidentally also led to
filtering out unwanted events in user space instead of gpiolib kernel
code. I then noticed that programs don't behave correctly and tracked
it down to an issue in gpiolib.c.

Please take a look at the fix. The bug has been there for some time and
it's quite late in the release cycle, but I believe it should still go
in v4.12 since currently the character device interface doesn't do what
it promises to.

Bartosz Golaszewski (1):
  gpiolib: fix filtering out unwanted events

 drivers/gpio/gpiolib.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

-- 
2.9.3

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH] gpiolib: fix filtering out unwanted events
  2017-06-23 11:45 [PATCH] gpiolib: fix filtering out unwanted events Bartosz Golaszewski
@ 2017-06-23 11:45 ` Bartosz Golaszewski
  2017-06-29  9:33   ` Linus Walleij
  2017-06-23 14:09 ` Bartosz Golaszewski
  1 sibling, 1 reply; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-06-23 11:45 UTC (permalink / raw)
  To: Linus Walleij; +Cc: linux-gpio, linux-kernel, Bartosz Golaszewski

GPIOEVENT_REQUEST_BOTH_EDGES is not a single flag, but a binary OR of
GPIOEVENT_REQUEST_RISING_EDGE and GPIOEVENT_REQUEST_FALLING_EDGE.

The expression 'le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES' we'll get
evaluated to true even if only one event type was requested.

Fix it by checking both RISING & FALLING flags explicitly.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/gpio/gpiolib.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5db4413..a42a1ee 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -708,7 +708,8 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p)
 
 	ge.timestamp = ktime_get_real_ns();
 
-	if (le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES) {
+	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
+	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
 		int level = gpiod_get_value_cansleep(le->desc);
 
 		if (level)
-- 
2.9.3

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] gpiolib: fix filtering out unwanted events
  2017-06-23 11:45 [PATCH] gpiolib: fix filtering out unwanted events Bartosz Golaszewski
  2017-06-23 11:45 ` Bartosz Golaszewski
@ 2017-06-23 14:09 ` Bartosz Golaszewski
  1 sibling, 0 replies; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-06-23 14:09 UTC (permalink / raw)
  To: Linus Walleij; +Cc: linux-gpio, linux-kernel, Bartosz Golaszewski

2017-06-23 13:45 GMT+02:00 Bartosz Golaszewski <brgl@bgdev.pl>:
> Hi Linux,
>

s/Linux/Linus :)

Bartosz

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] gpiolib: fix filtering out unwanted events
  2017-06-23 11:45 ` Bartosz Golaszewski
@ 2017-06-29  9:33   ` Linus Walleij
  2017-06-29 11:03     ` Bartosz Golaszewski
  0 siblings, 1 reply; 6+ messages in thread
From: Linus Walleij @ 2017-06-29  9:33 UTC (permalink / raw)
  To: Bartosz Golaszewski; +Cc: linux-gpio, linux-kernel

On Fri, Jun 23, 2017 at 1:45 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> GPIOEVENT_REQUEST_BOTH_EDGES is not a single flag, but a binary OR of
> GPIOEVENT_REQUEST_RISING_EDGE and GPIOEVENT_REQUEST_FALLING_EDGE.
>
> The expression 'le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES' we'll get
> evaluated to true even if only one event type was requested.
>
> Fix it by checking both RISING & FALLING flags explicitly.
>
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Patch applied for fixes.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] gpiolib: fix filtering out unwanted events
  2017-06-29  9:33   ` Linus Walleij
@ 2017-06-29 11:03     ` Bartosz Golaszewski
  2017-06-29 13:16       ` Linus Walleij
  0 siblings, 1 reply; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-06-29 11:03 UTC (permalink / raw)
  To: Linus Walleij; +Cc: linux-gpio, linux-kernel

2017-06-29 11:33 GMT+02:00 Linus Walleij <linus.walleij@linaro.org>:
> On Fri, Jun 23, 2017 at 1:45 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
>> GPIOEVENT_REQUEST_BOTH_EDGES is not a single flag, but a binary OR of
>> GPIOEVENT_REQUEST_RISING_EDGE and GPIOEVENT_REQUEST_FALLING_EDGE.
>>
>> The expression 'le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES' we'll get
>> evaluated to true even if only one event type was requested.
>>
>> Fix it by checking both RISING & FALLING flags explicitly.
>>
>> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>
> Patch applied for fixes.
>
> Yours,
> Linus Walleij

Thanks. I think this should also go to linux-stable (e.g. 4.9 LTS is
affected). Will you forward it or should I do it myself?

Thanks,
Bartosz

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] gpiolib: fix filtering out unwanted events
  2017-06-29 11:03     ` Bartosz Golaszewski
@ 2017-06-29 13:16       ` Linus Walleij
  0 siblings, 0 replies; 6+ messages in thread
From: Linus Walleij @ 2017-06-29 13:16 UTC (permalink / raw)
  To: Bartosz Golaszewski; +Cc: linux-gpio, linux-kernel

On Thu, Jun 29, 2017 at 1:03 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> 2017-06-29 11:33 GMT+02:00 Linus Walleij <linus.walleij@linaro.org>:
>> On Fri, Jun 23, 2017 at 1:45 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>>
>>> GPIOEVENT_REQUEST_BOTH_EDGES is not a single flag, but a binary OR of
>>> GPIOEVENT_REQUEST_RISING_EDGE and GPIOEVENT_REQUEST_FALLING_EDGE.
>>>
>>> The expression 'le->eflags & GPIOEVENT_REQUEST_BOTH_EDGES' we'll get
>>> evaluated to true even if only one event type was requested.
>>>
>>> Fix it by checking both RISING & FALLING flags explicitly.
>>>
>>> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>>
>> Patch applied for fixes.
>>
>> Yours,
>> Linus Walleij
>
> Thanks. I think this should also go to linux-stable (e.g. 4.9 LTS is
> affected). Will you forward it or should I do it myself?

I have added the stable tag so it should JustWork(TM).

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-06-29 13:16 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-06-23 11:45 [PATCH] gpiolib: fix filtering out unwanted events Bartosz Golaszewski
2017-06-23 11:45 ` Bartosz Golaszewski
2017-06-29  9:33   ` Linus Walleij
2017-06-29 11:03     ` Bartosz Golaszewski
2017-06-29 13:16       ` Linus Walleij
2017-06-23 14:09 ` Bartosz Golaszewski

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