| Message ID | 20240819-pmic-glink-v6-11-races-v2-2-88fe3ab1f0e2@quicinc.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | soc: qcom: pmic_glink: v6.11-rc bug fixes | expand |
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
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..bb6244f21e0a 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; + bool ucsi_registered; + bool pd_running; u8 read_buf[UCSI_BUF_SIZE]; }; @@ -244,8 +247,20 @@ 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; + bool pd_running; - ucsi_register(ucsi->ucsi); + spin_lock_irqsave(&ucsi->state_lock, flags); + pd_running = ucsi->pd_running; + spin_unlock_irqrestore(&ucsi->state_lock, flags); + + if (!ucsi->ucsi_registered && pd_running) { + ucsi_register(ucsi->ucsi); + ucsi->ucsi_registered = true; + } else if (ucsi->ucsi_registered && !pd_running) { + ucsi_unregister(ucsi->ucsi); + ucsi->ucsi_registered = false; + } } static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) @@ -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; + 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);
Commit '635ce0db8956 ("soc: qcom: pmic_glink: don't traverse clients 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 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") 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> --- drivers/soc/qcom/pmic_glink.c | 10 +++++++++- drivers/usb/typec/ucsi/ucsi_glink.c | 27 ++++++++++++++++++++++----- 2 files changed, 31 insertions(+), 6 deletions(-)