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:

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_resume                apds990x_irq
-> apds990x_chip_on              if (!pm_runtime_suspended
    -> 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

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