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SubjectRe: Question about apds990x.ko
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The author of this driver as well as bh1770glc.ko is Samu Onkalo. His 
e-mail that was found as a contact in the module's source is invalid. I
tried to add him previous time (Question about bh1770glc.ko). The
message was not delivered then.

On 10.08.2017 18:07, Greg KH wrote:
> On Thu, Aug 10, 2017 at 05:57:30PM +0300, Anton Volkov wrote:
>> Hello.
>>
>> While searching for races in the Linux kernel I've come across
>> "drivers/misc/apds990x.ko" module. Here are questions that I came up with
>> while analyzing results. Lines are given using the info from Linux v4.12.
>>
>> Consider the following case:
>>
>> Thread 1: Thread 2:
>> apds990x_suspend
>> apds990x_resume apds990x_irq
>> -> apds990x_chip_on if (!pm_runtime_suspended
>> (chip->client->dev)){
>> -> apds990x_configure if (status & APDS990X_ST_AINT) {
>> chip->again_meas = 1 chip->again_meas = chip->again_next
>> (apds990x.c: line 571) (apds990x.c: line 505)
>> }
>> }
>>
>> First question. Is this race feasible from your point of view?
>> Second question. The check for the device suspension status
>> (pm_runtime_suspended()) is present in the interrupt handler, but the
>> functions pm_runtime_set_suspended / pm_runtime_set_active are not used in
>> apds990x_suspend / apds990x_resume respectively. Do you know about any other
>> method being used to make the modification of suspension status?
>
> No idea, sorry. Maybe the driver authors know?
>
> greg k-h
>

--
-- Anton Volkov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
e-mail: avolkov@ispras.ru

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