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Date: Wed, 3 Apr 2024 10:17:47 -0500
From: Andrew Halaney <ahalaney@redhat.com>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Bjorn Andersson <andersson@kernel.org>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Neil Armstrong <neil.armstrong@linaro.org>, 
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] soc: qcom: pmic_glink: don't traverse clients
 list without a lock
Message-ID: <cnpl3m4r76wbpqgjb7vw3i6wldavpvrprd7nxrbor3s4v5kuky@wixormy7sdmx>
References: <20240403-pmic-glink-fix-clients-v2-0-aed4e02baacc@linaro.org>
 <20240403-pmic-glink-fix-clients-v2-1-aed4e02baacc@linaro.org>
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In-Reply-To: <20240403-pmic-glink-fix-clients-v2-1-aed4e02baacc@linaro.org>

On Wed, Apr 03, 2024 at 06:10:57AM +0300, Dmitry Baryshkov wrote:
> Take the client_lock before traversing the clients list at the
> pmic_glink_state_notify_clients() function. This is required to keep the
> list traversal safe from concurrent modification.
> 
> Fixes: 58ef4ece1e41 ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver")

Reviewed-by: Andrew Halaney <ahalaney@redhat.com>

> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  drivers/soc/qcom/pmic_glink.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
> index f913e9bd57ed..2b2cdf479654 100644
> --- a/drivers/soc/qcom/pmic_glink.c
> +++ b/drivers/soc/qcom/pmic_glink.c
> @@ -115,10 +115,12 @@ static int pmic_glink_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
>  
>  	hdr = data;
>  
> +	mutex_lock(&pg->client_lock);
>  	list_for_each_entry(client, &pg->clients, node) {
>  		if (client->id == le32_to_cpu(hdr->owner))
>  			client->cb(data, len, client->priv);
>  	}
> +	mutex_unlock(&pg->client_lock);
>  
>  	return 0;
>  }
> @@ -168,8 +170,10 @@ static void pmic_glink_state_notify_clients(struct pmic_glink *pg)
>  	}
>  
>  	if (new_state != pg->client_state) {
> +		mutex_lock(&pg->client_lock);
>  		list_for_each_entry(client, &pg->clients, node)
>  			client->pdr_notify(client->priv, new_state);
> +		mutex_unlock(&pg->client_lock);
>  		pg->client_state = new_state;
>  	}
>  }
> 
> -- 
> 2.39.2
> 
>