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net: qrtr: start MHI channel after endpoit creation 

MHI channel may generates event/interrupt right after enabling.
It may leads to 2 race conditions issues.

1)
Such event may be dropped by qcom_mhi_qrtr_dl_callback() at check:

	if (!qdev || mhi_res->transaction_status)
		return;

Because dev_set_drvdata(&mhi_dev->dev, qdev) may be not performed at
this moment. In this situation qrtr-ns will be unable to enumerate
services in device.
---------------------------------------------------------------

2)
Such event may come at the moment after dev_set_drvdata() and
before qrtr_endpoint_register(). In this case kernel will panic with
accessing wrong pointer at qcom_mhi_qrtr_dl_callback():

	rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr,
				mhi_res->bytes_xferd);

Because endpoint is not created yet.
--------------------------------------------------------------
So move mhi_prepare_for_transfer_autoqueue after endpoint creation
to fix it.

Fixes: a2e2cc0dbb ("net: qrtr: Start MHI channels during init")
Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>
Reviewed-by: Hemant Kumar <quic_hemantk@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Maxim Kochetkov 2022-08-11 12:48:40 +03:00 committed by David S. Miller
parent 7778856731
commit 68a838b84e
1 changed files with 7 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
net/qrtr/mhi.c
View File

@ -78,11 +78,6 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
struct qrtr_mhi_dev *qdev;
int rc;
/* start channels */
rc = mhi_prepare_for_transfer_autoqueue(mhi_dev);
if (rc)
return rc;
qdev = devm_kzalloc(&mhi_dev->dev, sizeof(*qdev), GFP_KERNEL);
if (!qdev)
return -ENOMEM;
@ -96,6 +91,13 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
if (rc)
return rc;
/* start channels */
rc = mhi_prepare_for_transfer_autoqueue(mhi_dev);
if (rc) {
qrtr_endpoint_unregister(&qdev->ep);
return rc;
}
dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n");
return 0;