linux-kernel - Re: [PATCH 2/2] soundwire: debugfs: fix unbalanced pm_runtime

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Date:   Wed, 17 May 2023 11:47:35 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Vinod Koul <vkoul@...nel.org>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Péter Ujfalusi <peter.ujfalusi@...ux.intel.com>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 2/2] soundwire: debugfs: fix unbalanced pm_runtime_put()



On 5/17/23 11:37, Krzysztof Kozlowski wrote:
> If pm_runtime_resume_and_get() failed with -EACCES, the driver continued
> execution and finally called pm_runtime_put_autosuspend().  Since
> pm_runtime_resume_and_get() drops the usage counter on every error, this
> lead to double decrement of that counter.
> 
> Fixes: b275bf45ba1d ("soundwire: debugfs: Switch to sdw_read_no_pm")
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>

> ---
>  drivers/soundwire/debugfs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c
> index dea782e0edc4..c3a1a359ee5c 100644
> --- a/drivers/soundwire/debugfs.c
> +++ b/drivers/soundwire/debugfs.c
> @@ -56,8 +56,9 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data)
>  	if (!buf)
>  		return -ENOMEM;
>  
> -	ret = pm_runtime_resume_and_get(&slave->dev);
> +	ret = pm_runtime_get_sync(&slave->dev);
>  	if (ret < 0 && ret != -EACCES) {
> +		pm_runtime_put_noidle(&slave->dev);
>  		kfree(buf);
>  		return ret;
>  	}