component bind crash

[klogg]

1. insmod both drivers
2. rmmod it66121.ko
3. insmod it66121.ko ---> crash

[   37.933763] i2c i2c-1: Detecting IT66121 at address 0x4C on usb-0000:00:05.0-1
[   38.008557] i2c i2c-1: IT66121 found, revision 1
[   38.009515] it66121 1-004c: Probing IT66121 client
[   38.010453] it66121 1-004c: Found bridge it66121
[   38.011403] usb 2-1: Binding FL2000 master component
[   38.014640] BUG: unable to handle kernel NULL pointer dereference at 0000000000000179
[   38.016248] PGD 0 P4D 0 
[   38.016778] Oops: 0000 [#1] SMP PTI
[   38.017492] CPU: 0 PID: 309 Comm: insmod Tainted: G           OE     4.18.0-13-generic #14-Ubuntu
[   38.019272] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1ubuntu1 04/01/2014
[   38.020760] RIP: 0010:drm_dev_init+0x163/0x2f0 [drm]
[   38.021134] Code: 00 00 00 48 8b 05 85 f4 04 00 48 8b 78 08 e8 94 89 2f d7 49 89 c4 48 3d 00 f0 ff ff 0f 87 9b 00 00 00 48 89 43 58 48 8b 43 20 <f6> 80 79 01 00 00 80 74 14 be 02 00 00 00 48 89 df e8 57 fd ff ff 
[   38.022543] RSP: 0018:ffffa52c001ff7f0 EFLAGS: 00010283
[   38.022939] RAX: 0000000000000000 RBX: ffff9247c3dfd018 RCX: 0000000000000000
[   38.023473] RDX: 000000000e111300 RSI: 000000000e111300 RDI: 000000005c1ffe30
[   38.024005] RBP: ffffa52c001ff818 R08: 0000000000000000 R09: 0000000000000001
[   38.024538] R10: 00000000001fffff R11: 00000000ffffffff R12: ffff9247c469c980
[   38.025073] R13: ffff9247c405f0a0 R14: ffffffffc05851a0 R15: 0000000000000001
[   38.025606] FS:  00007feaee505b80(0000) GS:ffff9247c7a00000(0000) knlGS:0000000000000000
[   38.026210] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   38.026642] CR2: 0000000000000179 CR3: 0000000003cc8006 CR4: 0000000000360ef0
[   38.027178] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   38.027713] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   38.028246] Call Trace:
[   38.028437]  fl2000_bind+0x54/0x2b0 [fl2000]
[   38.028761]  try_to_bring_up_master+0x1d4/0x280
[   38.029103]  ? fl2000_bind+0x2b0/0x2b0 [fl2000]
[   38.029445]  component_add+0xa4/0x180
[   38.029725]  it66121_probe+0xb6/0xf0 [it66121]
[   38.030062]  i2c_device_probe+0x97/0x290
[   38.030361]  driver_probe_device+0x2e3/0x460
[   38.030684]  __device_attach_driver+0x97/0x100
[   38.031022]  ? __driver_attach+0x110/0x110
[   38.031334]  bus_for_each_drv+0x7b/0xc0
[   38.031626]  __device_attach+0xdd/0x160
[   38.031918]  device_initial_probe+0x13/0x20
[   38.032235]  bus_probe_device+0x95/0xa0
[   38.032527]  device_add+0x3a4/0x650
[   38.032793]  device_register+0x1a/0x20
[   38.033077]  i2c_new_device+0x168/0x360
[   38.033368]  i2c_detect+0x181/0x310
[   38.033635]  __process_new_driver+0x28/0x50
[   38.033951]  ? i2c_detect+0x310/0x310
[   38.034229]  bus_for_each_dev+0x74/0xb0
[   38.034519]  ? i2c_detect+0x310/0x310
[   38.034797]  i2c_for_each_dev+0x32/0x50
[   38.035090]  i2c_register_driver+0x5d/0x90
[   38.035400]  ? 0xffffffffc03e9000
[   38.035652]  it66121_driver_init+0x1c/0x1000 [it66121]
[   38.036040]  do_one_initcall+0x4a/0x1c4
[   38.036332]  ? free_pcp_prepare+0x4f/0xd0
[   38.036637]  ? _cond_resched+0x19/0x30
[   38.037002]  ? kmem_cache_alloc_trace+0xb8/0x1d0
[   38.037443]  ? do_init_module+0x27/0x220
[   38.037822]  do_init_module+0x60/0x220
[   38.038184]  load_module+0x14f4/0x1890
[   38.038547]  __do_sys_finit_module+0xbd/0x120
[   38.038967]  ? __do_sys_finit_module+0xbd/0x120
[   38.039401]  __x64_sys_finit_module+0x1a/0x20
[   38.039819]  do_syscall_64+0x5a/0x110
[   38.040173]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   38.040657] RIP: 0033:0x7feaee642219
[   38.041002] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 47 fc 0c 00 f7 d8 64 89 01 48 
[   38.042785] RSP: 002b:00007ffc9650f528 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   38.043510] RAX: ffffffffffffffda RBX: 0000555b537a07a0 RCX: 00007feaee642219
[   38.044189] RDX: 0000000000000000 RSI: 0000555b526b0338 RDI: 0000000000000003
[   38.044734] RBP: 0000555b526b0338 R08: 0000000000000000 R09: 00007feaee715000
[   38.045266] R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
[   38.045810] R13: 0000555b537a0760 R14: 0000000000000000 R15: 0000000000000000
[   38.046333] Modules linked in: it66121(OE+) fl2000(OE) drm_kms_helper fb_sys_fops syscopyarea sysfillrect sysimgblt drm kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper input_leds psmouse serio_raw i2c_piix4 pata_acpi mac_hid floppy qemu_fw_cfg 9pnet_virtio 9p 9pnet fscache [last unloaded: it66121]
[   38.048822] CR2: 0000000000000179
[   38.049075] ---[ end trace ca551b1c9b83ed08 ]---
[   38.049429] RIP: 0010:drm_dev_init+0x163/0x2f0 [drm]
[   38.049802] Code: 00 00 00 48 8b 05 85 f4 04 00 48 8b 78 08 e8 94 89 2f d7 49 89 c4 48 3d 00 f0 ff ff 0f 87 9b 00 00 00 48 89 43 58 48 8b 43 20 <f6> 80 79 01 00 00 80 74 14 be 02 00 00 00 48 89 df e8 57 fd ff ff 
[   38.051201] RSP: 0018:ffffa52c001ff7f0 EFLAGS: 00010283
[   38.051593] RAX: 0000000000000000 RBX: ffff9247c3dfd018 RCX: 0000000000000000
[   38.052124] RDX: 000000000e111300 RSI: 000000000e111300 RDI: 000000005c1ffe30
[   38.052655] RBP: ffffa52c001ff818 R08: 0000000000000000 R09: 0000000000000001
[   38.053186] R10: 00000000001fffff R11: 00000000ffffffff R12: ffff9247c469c980
[   38.053717] R13: ffff9247c405f0a0 R14: ffffffffc05851a0 R15: 0000000000000001
[   38.054247] FS:  00007feaee505b80(0000) GS:ffff9247c7a00000(0000) knlGS:0000000000000000
[   38.054848] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   38.055279] CR2: 0000000000000179 CR3: 0000000003cc8006 CR4: 0000000000360ef0
[   38.055811] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   38.056343] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400