On Mon, Aug 19, 2024 at 01:07:46PM -0700, Bjorn Andersson wrote:
Commit '635ce0db8956 ("soc: qcom: pmic_glink: don't traverse clients
Looks like you copied the wrong SHA again. This should be
9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")
as we discussed.
list without a lock")' moved the pmic_glink client list under a spinlock, as it is accessed by the rpmsg/glink callback, which in turn is invoked from IRQ context.
This means that ucsi_unregister() is now called from IRQ context, which
And this should be "atomic context" as pdr notifications are done from a worker thread.
isn't feasible as it's expecting a sleepable context. An effort is under way to get GLINK to invoke its callbacks in a sleepable context, but until then lets schedule the unregistration.
A side effect of this is that ucsi_unregister() can now happen after the remote processor, and thereby the communication link with it, is gone. pmic_glink_send() is amended with a check to avoid the resulting NULL pointer dereference. This does however result in the user being informed about this error by the following entry in the kernel log:
ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5
Fixes: 635ce0db8956 ("soc: qcom: pmic_glink: don't traverse clients list without a lock")
Fixes: 9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")
Cc: stable@vger.kernel.org Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Neil Armstrong neil.armstrong@linaro.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Tested-by: Amit Pundir amit.pundir@linaro.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com
@@ -269,11 +284,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) static void pmic_glink_ucsi_pdr_notify(void *priv, int state) { struct pmic_glink_ucsi *ucsi = priv;
- unsigned long flags;
- if (state == SERVREG_SERVICE_STATE_UP)
schedule_work(&ucsi->register_work);- else if (state == SERVREG_SERVICE_STATE_DOWN)
ucsi_unregister(ucsi->ucsi);
- spin_lock_irqsave(&ucsi->state_lock, flags);
- ucsi->pd_running = state == SERVREG_SERVICE_STATE_UP;
Add parentheses for readability?
- spin_unlock_irqrestore(&ucsi->state_lock, flags);
- schedule_work(&ucsi->register_work);
} static void pmic_glink_ucsi_destroy(void *data) @@ -320,6 +336,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev, INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register); init_completion(&ucsi->read_ack); init_completion(&ucsi->write_ack);
- spin_lock_init(&ucsi->state_lock); mutex_init(&ucsi->lock);
ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);
Looks good otherwise:
Reviewed-by: Johan Hovold johan+linaro@kernel.org
Johan