The patch is designed to help locate where the kernel is dying during the
startup sequence.

- Boot parameter "initcall_debug" causes the kernel to print out the
  address of each initcall before calling it.

  The kallsyms tables do not cover __init sections, so printing the
  symbolic version of these symbols doesn't work.  They need to be looked up
  in System.map.

- Detect whether an initcall returns with interrupts disabled or with a
  locking imbalance.  If it does, complain and then try to fix it up.