iio: imu: adis: Fix NULL pointer dereference in adis_init

Summary

In the Linux kernel, the following vulnerability has been resolved: iio: imu: adis: Fix NULL pointer dereference in adis_init The adis_init() function dereferences adis->ops to check if the individual function pointers (write, read, reset) are NULL, but does not first check if adis->ops itself is NULL. Drivers like adis16480, adis16490, adis16545 and others do not set custom ops and rely on adis_init() assigning the defaults. Since struct adis is zero-initialized by devm_iio_device_alloc(), adis->ops is NULL when adis_init() is called, causing a NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 pc : adis_init+0xc0/0x118 Call trace: adis_init+0xc0/0x118 adis16480_probe+0xe0/0x670 Fix this by checking if adis->ops is NULL before dereferencing it, falling through to assign the default ops in that case.