On Mon, Aug 19, 2024 at 01:07:45PM -0700, Bjorn Andersson wrote:
As pointed out by Stephen Boyd it is possible that during initialization of the pmic_glink child drivers, the protection-domain notifiers fires, and the associated work is scheduled, before the client registration returns and as a result the local "client" pointer has been initialized.
The outcome of this is a NULL pointer dereference as the "client" pointer is blindly dereferenced.
Timeline provided by Stephen: CPU0 CPU1
ucsi->client = NULL; devm_pmic_glink_register_client() client->pdr_notify(client->priv, pg->client_state) pmic_glink_ucsi_pdr_notify() schedule_work(&ucsi->register_work) <schedule away> pmic_glink_ucsi_register() ucsi_register() pmic_glink_ucsi_read_version() pmic_glink_ucsi_read() pmic_glink_ucsi_read() pmic_glink_send(ucsi->client) <client is NULL BAD> ucsi->client = client // Too late!
This code is identical across the altmode, battery manager and usci child drivers.
Resolve this by splitting the allocation of the "client" object and the registration thereof into two operations.
This only happens if the protection domain registry is populated at the time of registration, which by the introduction of commit '1ebcde047c54 ("soc: qcom: add pd-mapper implementation")' became much more likely.
Reported-by: Amit Pundir amit.pundir@linaro.org Closes: https://lore.kernel.org/all/CAMi1Hd2_a7TjA7J9ShrAbNOd_CoZ3D87twmO5t+nZxC9sX1... Reported-by: Johan Hovold johan@kernel.org Closes: https://lore.kernel.org/all/ZqiyLvP0gkBnuekL@hovoldconsulting.com/ Reported-by: Stephen Boyd swboyd@chromium.org Closes: https://lore.kernel.org/all/CAE-0n52JgfCBWiFQyQWPji8cq_rCsviBpW-m72YitgNfdaE... Fixes: 58ef4ece1e41 ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver") Cc: stable@vger.kernel.org Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Neil Armstrong neil.armstrong@linaro.org Tested-by: Amit Pundir amit.pundir@linaro.org Signed-off-by: Bjorn Andersson quic_bjorande@quicinc.com
diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c index 9ebc0ba35947..58ec91767d79 100644 --- a/drivers/soc/qcom/pmic_glink.c +++ b/drivers/soc/qcom/pmic_glink.c @@ -66,15 +66,14 @@ static void _devm_pmic_glink_release_client(struct device *dev, void *res) spin_unlock_irqrestore(&pg->client_lock, flags); } -struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
unsigned int id,void (*cb)(const void *, size_t, void *),void (*pdr)(void *, int),void *priv)+struct pmic_glink_client *devm_pmic_glink_new_client(struct device *dev,
Please consider renaming this one
devm_pmic_glink_alloc_client()
(or devm_pmic_glink_client_alloc()) which is more conventional for kernel code than using "new".
unsigned int id,void (*cb)(const void *, size_t, void *),void (*pdr)(void *, int),void *priv){ struct pmic_glink_client *client; struct pmic_glink *pg = dev_get_drvdata(dev->parent);
- unsigned long flags;
client = devres_alloc(_devm_pmic_glink_release_client, sizeof(*client), GFP_KERNEL); if (!client)
Looks good otherwise:
Reviewed-by: Johan Hovold johan+linaro@kernel.org
Johan