[PATCH v3] media: as102: initialize mutexes before registering frontend

[Adriano Cordova <adrianox@gmail.com>]

The bus adapter mutex and the stream mutex are initialized after the
frontend has been registered, but the frontend's stream control
callback as102_stream_ctrl() takes the bus adapter mutex, which can be
used before it is initialized:

	INFO: trying to register non-static key.
	...
	as102_stream_ctrl+0x27/0xc0 drivers/media/usb/as102/as102_drv.c:259
	dvb_frontend_open+0x7eb/0x1410 drivers/media/dvb-core/dvb_frontend.c:2825

Initialize the mutexes before registering the adapter and frontend.

Fixes: 41b44e041811 ("[media] staging: as102: Initial import from Abilis")
Reported-by: syzbot+2a3de29133b40e8f69f3@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=2a3de29133b40e8f69f3
Tested-by: syzbot+2a3de29133b40e8f69f3@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Adriano Cordova <adrianox@gmail.com>
---
Changes since v1:
		- Succesfully passed available repo. Added Tested-by tag.
Changes since v2:
		- Reorder commit tags to fix warning.

 drivers/media/usb/as102/as102_drv.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/media/usb/as102/as102_drv.c b/drivers/media/usb/as102/as102_drv.c
index 6b1d3528a0a7..a6dd675689f5 100644
--- a/drivers/media/usb/as102/as102_drv.c
+++ b/drivers/media/usb/as102/as102_drv.c
@@ -287,6 +287,12 @@ int as102_dvb_register(struct as102_dev_t *as102_dev)
 	struct device *dev = &as102_dev->bus_adap.usb_dev->dev;
 	int ret;
 
+	/* init bus mutex for token locking */
+	mutex_init(&as102_dev->bus_adap.lock);
+
+	/* init start / stop stream mutex */
+	mutex_init(&as102_dev->sem);
+
 	ret = dvb_register_adapter(&as102_dev->dvb_adap,
 			   as102_dev->name, THIS_MODULE,
 			   dev, adapter_nr);
@@ -341,12 +347,6 @@ int as102_dvb_register(struct as102_dev_t *as102_dev)
 		goto efereg;
 	}
 
-	/* init bus mutex for token locking */
-	mutex_init(&as102_dev->bus_adap.lock);
-
-	/* init start / stop stream mutex */
-	mutex_init(&as102_dev->sem);
-
 	/*
 	 * try to load as102 firmware. If firmware upload failed, we'll be
 	 * able to upload it later.
-- 
2.51.0