6.10-stable review patch. If anyone has any objections, please let me know.
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From: Bjorn Andersson quic_bjorande@quicinc.com
commit 11bb2ffb679399f99041540cf662409905179e3a upstream.
Commit '9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")' 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 atomic 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: 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 Reviewed-by: Johan Hovold johan+linaro@kernel.org Tested-by: Johan Hovold johan+linaro@kernel.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com Link: https://lore.kernel.org/r/20240820-pmic-glink-v6-11-races-v3-2-eec53c750a04@... Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/soc/qcom/pmic_glink.c | 10 +++++++++- drivers/usb/typec/ucsi/ucsi_glink.c | 27 ++++++++++++++++++++++----- 2 files changed, 31 insertions(+), 6 deletions(-)
--- a/drivers/soc/qcom/pmic_glink.c +++ b/drivers/soc/qcom/pmic_glink.c @@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_client_regi 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);
--- a/drivers/usb/typec/ucsi/ucsi_glink.c +++ b/drivers/usb/typec/ucsi/ucsi_glink.c @@ -72,6 +72,9 @@ 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]; }; @@ -271,8 +274,20 @@ static void pmic_glink_ucsi_notify(struc 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) @@ -296,11 +311,12 @@ static void pmic_glink_ucsi_callback(con 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) @@ -348,6 +364,7 @@ static int pmic_glink_ucsi_probe(struct init_completion(&ucsi->read_ack); init_completion(&ucsi->write_ack); init_completion(&ucsi->sync_ack); + spin_lock_init(&ucsi->state_lock); mutex_init(&ucsi->lock);
ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);