soc: qcom: pmic_glink: Fix race during initialization

2024-09-04T11:30:12Z

commit 3568affcddd68743e25aa3ec1647d9b82797757b upstream. 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 Signed-off-by: Greg Kroah-Hartman

soc: qcom: pmic_glink: Introduce base PMIC GLINK driver

2023-02-04T18:54:30Z

The PMIC GLINK service runs on one of the co-processors of some modern Qualcomm platforms and implements USB-C and battery managements. It uses a message based protocol over GLINK for communication with the OS, hence the name. The driver implemented provides the rpmsg device for communication and uses auxiliary bus to spawn off individual devices in respective subsystem. The auxiliary devices are spawned off from a platform_device, so that the drm_bridge is available early, to allow the DisplayPort driver to probe even before the remoteproc has spun up. Signed-off-by: Bjorn Andersson Tested-by: Konrad Dybcio # SM8350 PDX215 Reviewed-by: Neil Armstrong Tested-by: Neil Armstrong # on SM8550-MTP & SM8450-HDK Signed-off-by: Bjorn Andersson Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20230201041853.1934355-3-quic_bjorande@quicinc.com

kernel/include/linux/soc/qcom/pmic_glink.h, branch linux-rolling-stable

soc: qcom: pmic_glink: Fix race during initialization

soc: qcom: pmic_glink: Introduce base PMIC GLINK driver