The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 44870a9e7a3c24acbb3f888b2a7cc22c9bdf7e7f Mon Sep 17 00:00:00 2001
From: Pavel Skripkin paskripkin@gmail.com Date: Thu, 19 Aug 2021 12:42:21 +0200 Subject: [PATCH] media: mxl111sf: change mutex_init() location
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 Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org
diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c index 7865fa0a8295..cd5861a30b6f 100644 --- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c +++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c @@ -931,8 +931,6 @@ static int mxl111sf_init(struct dvb_usb_device *d) .len = sizeof(eeprom), .buf = eeprom }, };
- mutex_init(&state->msg_lock); - ret = get_chip_info(state); if (mxl_fail(ret)) pr_err("failed to get chip info during probe"); @@ -1074,6 +1072,14 @@ 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 +1089,7 @@ 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 +1131,7 @@ 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 +1173,7 @@ 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 +1242,7 @@ 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 +1321,7 @@ 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 +1392,7 @@ 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,