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

tracing/mmiotrace: Add NULL check for mmio trace array in logging functions

mmio trace rw() and mmio trace mapping() retrieve mmio trace array into tr and pass it to trace mmiotrace rw() and trace mmiotrace map(). If these functions are invoked while mmio trace array is NULL (e.g. before initialization or after disabled), accessing tr->array buffer.buffer will result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of trace mmiotrace rw() and trace mmiotrace map().