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

i3c: Add NULL pointer check in i3c_master_queue_ibi()

The I3C master driver may receive an IBI from a target device that has not
been probed yet. In such cases, the master calls `i3c_master_queue_ibi()`
to queue an IBI work task, leading to "Unable to handle kernel read from
unreadable memory" and resulting in a kernel panic.

Typical IBI handling flow:
1. The I3C master scans target devices and probes their respective drivers.
2. The target device driver calls `i3c_device_request_ibi()` to enable IBI
   and assigns `dev->ibi = ibi`.
3. The I3C master receives an IBI from the target device and calls
   `i3c_master_queue_ibi()` to queue the target device driver’s IBI
   handler task.

However, since target device events are asynchronous to the I3C probe
sequence, step 3 may occur before step 2, causing `dev->ibi` to be `NULL`,
leading to a kernel panic.

Add a NULL pointer check in `i3c_master_queue_ibi()` to prevent accessing
an uninitialized `dev->ibi`, ensuring stability.

https://git.kernel.org/stable/c/6871a676aa534e8f218279672e0445c725f81026

https://git.kernel.org/stable/c/bd496a44f041da9ef3afe14d1d6193d460424e91

https://git.kernel.org/stable/c/d83b0c03ef8fbea2f03029a1cc1f5041f0e1d47f

https://git.kernel.org/stable/c/e6bba328578feb58c614c11868c259b40484c5fa

https://git.kernel.org/stable/c/fe4a4fc179b7898055555a11685915473588392e

https://git.kernel.org/stable/c/ff9d61db59bb27d16d3f872bff2620d50856b80c