accel/qaic: Fix bootlog initialization ordering

[ Upstream commit fd6e385 ]

As soon as we queue MHI buffers to receive the bootlog from the device,
we could be receiving data. Therefore all the resources needed to
process that data need to be setup prior to queuing the buffers.

We currently initialize some of the resources after queuing the buffers
which creates a race between the probe() and any data that comes back
from the device. If the uninitialized resources are accessed, we could
see page faults.

Fix the init ordering to close the race.

Fixes: 5f8df5c ("accel/qaic: Add bootlog debugfs")
Signed-off-by: Jeffrey Hugo <[email protected]>
Signed-off-by: Youssef Samir <[email protected]>
Reviewed-by: Jeff Hugo <[email protected]>
Reviewed-by: Carl Vanderlip <[email protected]>
Signed-off-by: Jeff Hugo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>

Author: quic-jhugo

drivers/accel/qaic/qaic_debugfs.c

@@ -251,6 +251,9 @@ static int qaic_bootlog_mhi_probe(struct mhi_device *mhi_dev, const struct mhi_d
 	if (ret)
 		goto destroy_workqueue;
 
+	dev_set_drvdata(&mhi_dev->dev, qdev);
+	qdev->bootlog_ch = mhi_dev;
+
 	for (i = 0; i < BOOTLOG_POOL_SIZE; i++) {
 		msg = devm_kzalloc(&qdev->pdev->dev, sizeof(*msg), GFP_KERNEL);
 		if (!msg) {
@@ -266,8 +269,6 @@ static int qaic_bootlog_mhi_probe(struct mhi_device *mhi_dev, const struct mhi_d
 			goto mhi_unprepare;
 	}
 
-	dev_set_drvdata(&mhi_dev->dev, qdev);
-	qdev->bootlog_ch = mhi_dev;
 	return 0;
 
 mhi_unprepare: