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From: Pavel Skripkin <paskripkin@gmail.com>
To: mkrufky@linuxtv.org, mchehab@kernel.org, crope@iki.fi, sean@mess.org
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	Pavel Skripkin <paskripkin@gmail.com>,
	syzbot+5ca0bf339f13c4243001@syzkaller.appspotmail.com
Subject: [PATCH v2] media: mxl111sf: change mutex_init() location
Date: Thu, 19 Aug 2021 13:38:59 +0300	[thread overview]
Message-ID: <20210819103859.17498-1-paskripkin@gmail.com> (raw)
In-Reply-To: <20210819092908.GA27679@gofer.mess.org>

Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized
mutex. The problem was in wrong mutex_init() location.

Previous mutex_init(&state->msg_lock) call was in ->init() function, but
dvb_usbv2_init() has this order of calls:

	dvb_usbv2_init()
	  dvb_usbv2_adapter_init()
	    dvb_usbv2_adapter_frontend_init()
	      props->frontend_attach()

	  props->init()

Since mxl111sf_* devices call mxl111sf_ctrl_msg() in ->frontend_attach()
internally we need to initialize state->msg_lock before
frontend_attach(). To achieve it, ->probe() call added to all mxl111sf_*
devices, which will simply initiaize mutex.

Reported-and-tested-by: syzbot+5ca0bf339f13c4243001@syzkaller.appspotmail.com
Fixes: 8572211842af ("[media] mxl111sf: convert to new DVB USB")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---

Changes in v2:
	Addressed same bug in all mxl111sf_* devices by adding ->probe
	call

---
 drivers/media/usb/dvb-usb-v2/mxl111sf.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index 7865fa0a8295..b9714ce994d1 100644
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -1074,6 +1074,14 @@ static int mxl111sf_get_stream_config_dvbt(struct dvb_frontend *fe,
 	return 0;
 }
 
+static int mxl111sf_probe(struct dvb_usb_device *dev)
+{
+	struct mxl111sf_state *state = d_to_priv(dev);
+
+	mutex_init(&state->msg_lock);
+	return 0;
+}
+
 static struct dvb_usb_device_properties mxl111sf_props_dvbt = {
 	.driver_name = KBUILD_MODNAME,
 	.owner = THIS_MODULE,
@@ -1083,6 +1091,7 @@ static struct dvb_usb_device_properties mxl111sf_props_dvbt = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_dvbt,
 	.tuner_attach      = mxl111sf_attach_tuner,
@@ -1124,6 +1133,7 @@ static struct dvb_usb_device_properties mxl111sf_props_atsc = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_atsc,
 	.tuner_attach      = mxl111sf_attach_tuner,
@@ -1165,6 +1175,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mh = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_mh,
 	.tuner_attach      = mxl111sf_attach_tuner,
@@ -1233,6 +1244,7 @@ static struct dvb_usb_device_properties mxl111sf_props_atsc_mh = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_atsc_mh,
 	.tuner_attach      = mxl111sf_attach_tuner,
@@ -1311,6 +1323,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mercury = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_mercury,
 	.tuner_attach      = mxl111sf_attach_tuner,
@@ -1381,6 +1394,7 @@ static struct dvb_usb_device_properties mxl111sf_props_mercury_mh = {
 	.generic_bulk_ctrl_endpoint = 0x02,
 	.generic_bulk_ctrl_endpoint_response = 0x81,
 
+	.probe             = mxl111sf_probe,
 	.i2c_algo          = &mxl111sf_i2c_algo,
 	.frontend_attach   = mxl111sf_frontend_attach_mercury_mh,
 	.tuner_attach      = mxl111sf_attach_tuner,
-- 
2.32.0


  parent reply	other threads:[~2021-08-19 10:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 21:38 [PATCH] " Pavel Skripkin
2021-08-15  8:37 ` Sean Young
2021-08-15  8:49   ` Pavel Skripkin
2021-08-15  9:06     ` Pavel Skripkin
2021-08-19  9:29       ` Sean Young
2021-08-19  9:31         ` Pavel Skripkin
2021-08-19 10:38         ` Pavel Skripkin [this message]
2021-08-19 10:42           ` [PATCH v3] " Pavel Skripkin
2021-09-12 15:49             ` Pavel Skripkin
2021-09-15 16:40               ` Sean Young

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