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    Subject[PATCH 5.9 535/757] pwm: img: Fix null pointer access in probe
    Date
    From: Hauke Mehrtens <hauke@hauke-m.de>

    [ Upstream commit b39c0615d0667b3a6f2f5c4bf99ffadf3b518bb1 ]

    dev_get_drvdata() is called in img_pwm_runtime_resume() before the
    driver data is set.
    When pm_runtime_enabled() returns false in img_pwm_probe() it calls
    img_pwm_runtime_resume() which results in a null pointer access.

    This patch fixes the problem by setting the driver data earlier in the
    img_pwm_probe() function.

    This crash was seen when booting the Imagination Technologies Creator
    Ci40 (Marduk) with kernel 5.4 in OpenWrt.

    Fixes: e690ae526216 ("pwm: img: Add runtime PM")
    Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
    Acked-by: Lee Jones <lee.jones@linaro.org>
    Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/pwm/pwm-img.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
    index 599a0f66a3845..a34d95ed70b20 100644
    --- a/drivers/pwm/pwm-img.c
    +++ b/drivers/pwm/pwm-img.c
    @@ -277,6 +277,8 @@ static int img_pwm_probe(struct platform_device *pdev)
    return PTR_ERR(pwm->pwm_clk);
    }

    + platform_set_drvdata(pdev, pwm);
    +
    pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
    pm_runtime_use_autosuspend(&pdev->dev);
    pm_runtime_enable(&pdev->dev);
    @@ -313,7 +315,6 @@ static int img_pwm_probe(struct platform_device *pdev)
    goto err_suspend;
    }

    - platform_set_drvdata(pdev, pwm);
    return 0;

    err_suspend:
    --
    2.25.1


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