CVE-2021-47583

In the Linux kernel, the following vulnerability has been resolved:

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.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.