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    SubjectQuestion about apds990x.ko
    Date
    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?

    Thank you for your time.

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

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