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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 <[email protected]>
Closes: https://lore.kernel.org/all/CAMi1Hd2_a7TjA7J9ShrAbNOd_CoZ3D87twmO5t+nZxC9sX18tA@mail.gmail.com/
Reported-by: Johan Hovold <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Reported-by: Stephen Boyd <[email protected]>
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: [email protected]
Reviewed-by: Heikki Krogerus <[email protected]>
Reviewed-by: Neil Armstrong <[email protected]>
Tested-by: Amit Pundir <[email protected]>
Reviewed-by: Johan Hovold <[email protected]>
Acked-by: Sebastian Reichel <[email protected]>
Tested-by: Johan Hovold <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>
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