That happened because hdev->power_on is already called before
sdio_set_drvdata which btmtksdio_interrupt handler relies on is not
properly set up.
The details are shown as the below: hci_register_dev would run
queue_work(hdev->req_workqueue, &hdev->power_on) as WQ_HIGHPRI
workqueue_struct to complete the power-on sequeunce and thus hci_power_on
may run before sdio_set_drvdata is done in btmtksdio_probe.
The hci_dev_do_open in hci_power_on would initialize the device and enable
the interrupt and thus it is possible that btmtksdio_interrupt is being
called right before sdio_set_drvdata is filled out.
When btmtksdio_interrupt is being called and sdio_set_drvdata is not filled
, the kernel oops is going to happen because btmtksdio_interrupt access an
uninitialized pointer.
Fixes: 706dc795574b ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices") Reviewed-by: Mark Chen <markyawenchen@gmail.com> Co-developed-by: Sean Wang <sean.wang@mediatek.com> Signed-off-by: Sean Wang <sean.wang@mediatek.com> Signed-off-by: Yake Yang <yake.yang@mediatek.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>