This is a note to let you know that I've just added the patch titled media: mxl111sf: change mutex_init() location to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-mxl111sf-change-mutex_init-location.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 44870a9e7a3c24acbb3f888b2a7cc22c9bdf7e7f Mon Sep 17 00:00:00 2001 From: Pavel Skripkin <paskripkin@xxxxxxxxx> Date: Thu, 19 Aug 2021 12:42:21 +0200 Subject: media: mxl111sf: change mutex_init() location From: Pavel Skripkin <paskripkin@xxxxxxxxx> commit 44870a9e7a3c24acbb3f888b2a7cc22c9bdf7e7f upstream. 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@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 8572211842af ("[media] mxl111sf: convert to new DVB USB") Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> Signed-off-by: Sean Young <sean@xxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/media/usb/dvb-usb-v2/mxl111sf.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) --- 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_ .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_dv 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 .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 .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 .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 .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 .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 .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, Patches currently in stable-queue which might be from paskripkin@xxxxxxxxx are queue-5.4/media-mxl111sf-change-mutex_init-location.patch