From: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Tested-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Reviewed-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Tested-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240820-pmic-glink-v6-11-races-v3-2-eec53c750a04@xxxxxxxxxxx
Signed-off-by: Bjorn Andersson <andersson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from quic_bjorande@xxxxxxxxxxx are
queue-6.10/soc-qcom-pmic_glink-actually-communicate-when-remote-goes-down.patch
queue-6.10/usb-typec-ucsi-move-unregister-out-of-atomic-section.patch
queue-6.10/soc-qcom-pmic_glink-fix-race-during-initialization.patch
