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: avol...@ispras.ru
