staging: media: max96712: fix kernel oops when removing module

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

staging: media: max96712: fix kernel oops when removing module

The following kernel oops is thrown when trying to remove the max96712

module:

Unable to handle kernel paging request at virtual address 00007375746174db

Mem abort info:

ESR = 0x0000000096000004

EC = 0x25: DABT (current EL), IL = 32 bits

SET = 0, FnV = 0

EA = 0, S1PTW = 0

FSC = 0x04: level 0 translation fault

Data abort info:

ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000

CM = 0, WnR = 0, TnD = 0, TagAccess = 0

GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0

user pgtable: 4k pages, 48-bit VAs, pgdp=000000010af89000

[00007375746174db] pgd=0000000000000000, p4d=0000000000000000

Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP

Modules linked in: crct10dif_ce polyval_ce mxc_jpeg_encdec flexcan

snd_soc_fsl_sai snd_soc_fsl_asoc_card snd_soc_fsl_micfil dwc_mipi_csi2

imx_csi_formatter polyval_generic v4l2_jpeg imx_pcm_dma can_dev

snd_soc_imx_audmux snd_soc_wm8962 snd_soc_imx_card snd_soc_fsl_utils

max96712(C-) rpmsg_ctrl rpmsg_char pwm_fan fuse

[last unloaded: imx8_isi]

CPU: 0 UID: 0 PID: 754 Comm: rmmod

Tainted: G C 6.12.0-rc6-06364-g327fec852c31 #17

Tainted: [C]=CRAP

Hardware name: NXP i.MX95 19X19 board (DT)

pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)

pc : led_put+0x1c/0x40

lr : v4l2_subdev_put_privacy_led+0x48/0x58

sp : ffff80008699bbb0

x29: ffff80008699bbb0 x28: ffff00008ac233c0 x27: 0000000000000000

x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000

x23: ffff000080cf1170 x22: ffff00008b53bd00 x21: ffff8000822ad1c8

x20: ffff000080ff5c00 x19: ffff00008b53be40 x18: 0000000000000000

x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000

x14: 0000000000000004 x13: ffff0000800f8010 x12: 0000000000000000

x11: ffff000082acf5c0 x10: ffff000082acf478 x9 : ffff0000800f8010

x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : fefefeff6364626d

x5 : 8080808000000000 x4 : 0000000000000020 x3 : 00000000553a3dc1

x2 : ffff00008ac233c0 x1 : ffff00008ac233c0 x0 : ff00737574617473

Call trace:

led_put+0x1c/0x40

v4l2_subdev_put_privacy_led+0x48/0x58

v4l2_async_unregister_subdev+0x2c/0x1a4

max96712_remove+0x1c/0x38 [max96712]

i2c_device_remove+0x2c/0x9c

device_remove+0x4c/0x80

device_release_driver_internal+0x1cc/0x228

driver_detach+0x4c/0x98

bus_remove_driver+0x6c/0xbc

driver_unregister+0x30/0x60

i2c_del_driver+0x54/0x64

max96712_i2c_driver_exit+0x18/0x1d0 [max96712]

__arm64_sys_delete_module+0x1a4/0x290

invoke_syscall+0x48/0x10c

el0_svc_common.constprop.0+0xc0/0xe0

do_el0_svc+0x1c/0x28

el0_svc+0x34/0xd8

el0t_64_sync_handler+0x120/0x12c

el0t_64_sync+0x190/0x194

Code: f9000bf3 aa0003f3 f9402800 f9402000 (f9403400)

---[ end trace 0000000000000000 ]---

This happens because in v4l2_i2c_subdev_init(), the i2c_set_cliendata()

is called again and the data is overwritten to point to sd, instead of

priv. So, in remove(), the wrong pointer is passed to

v4l2_async_unregister_subdev(), leading to a crash.