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Date: Tue, 2 Apr 2024 12:56:32 -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 1/2] soc: qcom: pmic_glink: don't traverse clients list
 without a lock
Message-ID: <bnxrstkmjmmbhzrqncfwwnxa5vpx3ioysykqr3sbiirlatneu4@vlewrjturppo>
References: <20240402-pmic-glink-fix-clients-v1-0-885440b81c65@linaro.org>
 <20240402-pmic-glink-fix-clients-v1-1-885440b81c65@linaro.org>
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In-Reply-To: <20240402-pmic-glink-fix-clients-v1-1-885440b81c65@linaro.org>

On Tue, Apr 02, 2024 at 08:07:06PM +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")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  drivers/soc/qcom/pmic_glink.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
> index f913e9bd57ed..c999358771b3 100644
> --- a/drivers/soc/qcom/pmic_glink.c
> +++ b/drivers/soc/qcom/pmic_glink.c
> @@ -168,8 +168,10 @@ static void pmic_glink_state_notify_clients(struct pmic_glink *pg)
>  	}

Does pmic_glink_rpmsg_callback() deserve similar locking when traversing
the clients list?

>  
>  	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
> 
>