On 19/08/2024 01:17, 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@vger.kernel.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com
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)
Looks good, I'll run it on the 8550/8650 platforms
Reviewed-by: Neil Armstrong neil.armstrong@linaro.org