On Sun, Aug 18, 2024 at 04:17:38PM -0700, Bjorn Andersson wrote: > Commit 'caa855189104 ("soc: qcom: pmic_glink: Fix race during > initialization")' 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 > 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, but it becomes expecting to see a failing send > upon shutting down the remote processor (e.g. during a restart following > a firmware crash): > > ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5 > > Fixes: caa855189104 ("soc: qcom: pmic_glink: Fix race during initialization") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > --- > drivers/soc/qcom/pmic_glink.c | 10 +++++++++- > drivers/usb/typec/ucsi/ucsi_glink.c | 28 +++++++++++++++++++++++----- > 2 files changed, 32 insertions(+), 6 deletions(-) > > diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c > index 58ec91767d79..e4747f1d3da5 100644 > --- a/drivers/soc/qcom/pmic_glink.c > +++ b/drivers/soc/qcom/pmic_glink.c > @@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_register_client); > int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len) > { > struct pmic_glink *pg = client->pg; > + int ret; > > - return rpmsg_send(pg->ept, data, len); > + mutex_lock(&pg->state_lock); > + if (!pg->ept) > + ret = -ECONNRESET; > + else > + ret = rpmsg_send(pg->ept, data, len); > + mutex_unlock(&pg->state_lock); > + > + return ret; > } > EXPORT_SYMBOL_GPL(pmic_glink_send); > > diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c > index ac53a81c2a81..a33056eec83d 100644 > --- a/drivers/usb/typec/ucsi/ucsi_glink.c > +++ b/drivers/usb/typec/ucsi/ucsi_glink.c > @@ -68,6 +68,9 @@ struct pmic_glink_ucsi { > > struct work_struct notify_work; > struct work_struct register_work; > + spinlock_t state_lock; > + unsigned int pdr_state; > + unsigned int new_pdr_state; > > u8 read_buf[UCSI_BUF_SIZE]; > }; > @@ -244,8 +247,22 @@ static void pmic_glink_ucsi_notify(struct work_struct *work) > static void pmic_glink_ucsi_register(struct work_struct *work) > { > struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work); > + unsigned long flags; > + unsigned int new_state; > + > + spin_lock_irqsave(&ucsi->state_lock, flags); > + new_state = ucsi->new_pdr_state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + > + if (ucsi->pdr_state != SERVREG_SERVICE_STATE_UP) { > + if (new_state == SERVREG_SERVICE_STATE_UP) > + ucsi_register(ucsi->ucsi); > + } else { > + if (new_state == SERVREG_SERVICE_STATE_DOWN) > + ucsi_unregister(ucsi->ucsi); > + } > > - ucsi_register(ucsi->ucsi); > + ucsi->pdr_state = new_state; > } > > static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) > @@ -269,11 +286,12 @@ 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->new_pdr_state = state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + schedule_work(&ucsi->register_work); > } > > static void pmic_glink_ucsi_destroy(void *data) > > -- > 2.34.1 -- heikki