[BUG] cx25840_init -- WARN_ON(1) reached in the seed's own task via a sysfs bind

[Farhad Alemi]

Hello,

As part of the kernel research at ASU's SEFCOM
lab, we hit the crash below. Crash reports can be found here:

  https://github.com/farhad-alemi/public_bug_reports/tree/main/142-media-cx25840-warn_on-generic-mode/

  WARNING: drivers/media/i2c/cx25840/cx25840-core.c:2313 at
cx25840_init+0xa3/0x110 drivers/media/i2c/cx25840/cx25840-core.c:2313,
CPU#1: kworker/1:3/10687
  Modules linked in:
  CPU: 1 UID: 0 PID: 10687 Comm: kworker/1:3 Tainted: G             L
    7.1.0-rc5 #1 PREEMPT(full)
  Tainted: [L]=SOFTLOCKUP
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
  Workqueue: usb_hub_wq hub_event
  RIP: 0010:cx25840_init+0xa3/0x110
drivers/media/i2c/cx25840/cx25840-core.c:2313
  Call Trace:
   <TASK>
   cxusb_medion_register_analog_subdevs
drivers/media/usb/dvb-usb/cxusb-analog.c:1730 [inline]
   cxusb_medion_register_analog+0x2fa/0x1110
drivers/media/usb/dvb-usb/cxusb-analog.c:1793
   cxusb_probe+0x664/0x710 drivers/media/usb/dvb-usb/cxusb.c:1615
   usb_probe_interface+0x657/0xc70 drivers/usb/core/driver.c:396
   really_probe+0x267/0xaf0 drivers/base/dd.c:709
   __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
   driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
   __device_attach_driver+0x279/0x430 drivers/base/dd.c:1029
   bus_for_each_drv+0x257/0x2f0 drivers/base/bus.c:500
   __device_attach+0x2c3/0x450 drivers/base/dd.c:1101

Our reproducer.c is available upon request.

Happy to test a patch if that would help.

Regards,