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: a2e2cc0dbb11 ("net: qrtr: Start MHI channels during init")
Signed-off-by: Maxim Kochetkov <fido_max@xxxxxxxx>
Reviewed-by: Hemant Kumar <quic_hemantk@xxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>
---
net/qrtr/mhi.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
index 18196e1c8c2f..17520d9e7a51 100644
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -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 +91,11 @@ 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)
+ return rc;
+
dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n");
return 0;
--
2.34.1
