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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Mark Chen <markyawenchen@gmail.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Yake Yang <yake.yang@mediatek.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0619/1017] Bluetooth: btmtksdio: Fix kernel oops in btmtksdio_interrupt
Date:   Tue,  5 Apr 2022 09:25:32 +0200
Message-Id: <20220405070412.656676419@linuxfoundation.org>
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From: Yake Yang <yake.yang@mediatek.com>

[ Upstream commit b062a0b9c1dc1ff63094337dccfe1568d5b62023 ]

Fix the following kernel oops in btmtksdio_interrrupt

[   14.339134]  btmtksdio_interrupt+0x28/0x54
[   14.339139]  process_sdio_pending_irqs+0x68/0x1a0
[   14.339144]  sdio_irq_work+0x40/0x70
[   14.339154]  process_one_work+0x184/0x39c
[   14.339160]  worker_thread+0x228/0x3e8
[   14.339168]  kthread+0x148/0x3ac
[   14.339176]  ret_from_fork+0x10/0x30

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: 9aebfd4a2200 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/bluetooth/btmtksdio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index 1cbdeca1fdc4..ff1f5dfbb6db 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -981,6 +981,8 @@ static int btmtksdio_probe(struct sdio_func *func,
 	hdev->manufacturer = 70;
 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
 
+	sdio_set_drvdata(func, bdev);
+
 	err = hci_register_dev(hdev);
 	if (err < 0) {
 		dev_err(&func->dev, "Can't register HCI device\n");
@@ -988,8 +990,6 @@ static int btmtksdio_probe(struct sdio_func *func,
 		return err;
 	}
 
-	sdio_set_drvdata(func, bdev);
-
 	/* pm_runtime_enable would be done after the firmware is being
 	 * downloaded because the core layer probably already enables
 	 * runtime PM for this func such as the case host->caps &
-- 
2.34.1