From 3568affcddd68743e25aa3ec1647d9b82797757b Mon Sep 17 00:00:00 2001 From: Bjorn Andersson Date: Tue, 20 Aug 2024 13:29:30 -0700 Subject: [PATCH] soc: qcom: pmic_glink: Fix race during initialization 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) pmic_glink_ucsi_register() ucsi_register() pmic_glink_ucsi_read_version() pmic_glink_ucsi_read() pmic_glink_ucsi_read() pmic_glink_send(ucsi->client) 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 Closes: https://lore.kernel.org/all/CAMi1Hd2_a7TjA7J9ShrAbNOd_CoZ3D87twmO5t+nZxC9sX18tA@mail.gmail.com/ Reported-by: Johan Hovold Closes: https://lore.kernel.org/all/ZqiyLvP0gkBnuekL@hovoldconsulting.com/ Reported-by: Stephen Boyd Closes: https://lore.kernel.org/all/CAE-0n52JgfCBWiFQyQWPji8cq_rCsviBpW-m72YitgNfdaEhQg@mail.gmail.com/ Fixes: 58ef4ece1e41 ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver") Cc: stable@vger.kernel.org Reviewed-by: Heikki Krogerus Reviewed-by: Neil Armstrong Tested-by: Amit Pundir Reviewed-by: Johan Hovold Acked-by: Sebastian Reichel Tested-by: Johan Hovold Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20240820-pmic-glink-v6-11-races-v3-1-eec53c750a04@quicinc.com Signed-off-by: Bjorn Andersson --- drivers/power/supply/qcom_battmgr.c | 16 +++++++++------ drivers/soc/qcom/pmic_glink.c | 28 +++++++++++++++++---------- drivers/soc/qcom/pmic_glink_altmode.c | 17 ++++++++++------ drivers/usb/typec/ucsi/ucsi_glink.c | 16 +++++++++------ include/linux/soc/qcom/pmic_glink.h | 11 ++++++----- 5 files changed, 55 insertions(+), 33 deletions(-) diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c index 46f36dcb185c..7cf19a39d986 100644 --- a/drivers/power/supply/qcom_battmgr.c +++ b/drivers/power/supply/qcom_battmgr.c @@ -1385,12 +1385,16 @@ static int qcom_battmgr_probe(struct auxiliary_device *adev, "failed to register wireless charing power supply\n"); } - battmgr->client = devm_pmic_glink_register_client(dev, - PMIC_GLINK_OWNER_BATTMGR, - qcom_battmgr_callback, - qcom_battmgr_pdr_notify, - battmgr); - return PTR_ERR_OR_ZERO(battmgr->client); + battmgr->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_BATTMGR, + qcom_battmgr_callback, + qcom_battmgr_pdr_notify, + battmgr); + if (IS_ERR(battmgr->client)) + return PTR_ERR(battmgr->client); + + pmic_glink_client_register(battmgr->client); + + return 0; } static const struct auxiliary_device_id qcom_battmgr_id_table[] = { diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c index 9ebc0ba35947..53b176d04fbd 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_client_alloc(struct device *dev, + 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) @@ -85,6 +84,18 @@ struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev, client->cb = cb; client->pdr_notify = pdr; client->priv = priv; + INIT_LIST_HEAD(&client->node); + + devres_add(dev, client); + + return client; +} +EXPORT_SYMBOL_GPL(devm_pmic_glink_client_alloc); + +void pmic_glink_client_register(struct pmic_glink_client *client) +{ + struct pmic_glink *pg = client->pg; + unsigned long flags; mutex_lock(&pg->state_lock); spin_lock_irqsave(&pg->client_lock, flags); @@ -95,11 +106,8 @@ struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev, spin_unlock_irqrestore(&pg->client_lock, flags); mutex_unlock(&pg->state_lock); - devres_add(dev, client); - - return client; } -EXPORT_SYMBOL_GPL(devm_pmic_glink_register_client); +EXPORT_SYMBOL_GPL(pmic_glink_client_register); int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len) { diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c index 1e0808b3cb93..463b1c528831 100644 --- a/drivers/soc/qcom/pmic_glink_altmode.c +++ b/drivers/soc/qcom/pmic_glink_altmode.c @@ -520,12 +520,17 @@ static int pmic_glink_altmode_probe(struct auxiliary_device *adev, return ret; } - altmode->client = devm_pmic_glink_register_client(dev, - altmode->owner_id, - pmic_glink_altmode_callback, - pmic_glink_altmode_pdr_notify, - altmode); - return PTR_ERR_OR_ZERO(altmode->client); + altmode->client = devm_pmic_glink_client_alloc(dev, + altmode->owner_id, + pmic_glink_altmode_callback, + pmic_glink_altmode_pdr_notify, + altmode); + if (IS_ERR(altmode->client)) + return PTR_ERR(altmode->client); + + pmic_glink_client_register(altmode->client); + + return 0; } static const struct auxiliary_device_id pmic_glink_altmode_id_table[] = { diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c index 16c328497e0b..f6f4fae40399 100644 --- a/drivers/usb/typec/ucsi/ucsi_glink.c +++ b/drivers/usb/typec/ucsi/ucsi_glink.c @@ -367,12 +367,16 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev, ucsi->port_orientation[port] = desc; } - ucsi->client = devm_pmic_glink_register_client(dev, - PMIC_GLINK_OWNER_USBC, - pmic_glink_ucsi_callback, - pmic_glink_ucsi_pdr_notify, - ucsi); - return PTR_ERR_OR_ZERO(ucsi->client); + ucsi->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_USBC, + pmic_glink_ucsi_callback, + pmic_glink_ucsi_pdr_notify, + ucsi); + if (IS_ERR(ucsi->client)) + return PTR_ERR(ucsi->client); + + pmic_glink_client_register(ucsi->client); + + return 0; } static void pmic_glink_ucsi_remove(struct auxiliary_device *adev) diff --git a/include/linux/soc/qcom/pmic_glink.h b/include/linux/soc/qcom/pmic_glink.h index fd124aa18c81..7cddf1027752 100644 --- a/include/linux/soc/qcom/pmic_glink.h +++ b/include/linux/soc/qcom/pmic_glink.h @@ -23,10 +23,11 @@ struct pmic_glink_hdr { int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len); -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_client_alloc(struct device *dev, + unsigned int id, + void (*cb)(const void *, size_t, void *), + void (*pdr)(void *, int), + void *priv); +void pmic_glink_client_register(struct pmic_glink_client *client); #endif