AZL-98175

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

tracing/mmiotrace: Add NULL check for mmiotracearray in logging functions

mmiotracerw() and mmiotracemapping() retrieve mmiotracearray into tr and pass it to __tracemmiotracerw() and _tracemmiotracemap(). If these functions are invoked while mmiotracearray is NULL (e.g. before initialization or after disabled), accessing tr->arraybuffer.buffer will result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of __tracemmiotracerw() and __tracemmiotracemap().