soc: qcom: pmic_glink: don't traverse clients list without a lock

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: 58ef4ec ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Tested-by: Xilin Wu <wuxilin123@gmail.com> # on QCS8550 AYN Odin 2
Link: https://lore.kernel.org/r/20240403-pmic-glink-fix-clients-v2-1-aed4e02baacc@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

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;
 	}
 }