---
- branch: MAIN
  date: Wed Jan 29 01:54:34 UTC 2020
  files:
  - new: '1.135'
    old: '1.134'
    path: src/sys/arch/x86/x86/x86_machdep.c
    pathrev: src/sys/arch/x86/x86/x86_machdep.c@1.135
    type: modified
  id: 20200129T015434Z.85e3c1b514a6b8916f93c0fc62fb27ac6f42451e
  log: |
    Fix startup crashes caused by wrong memory map handling

    init_x86_vm() takes the memory map from BIOS and EFI and selects
    regions suitable for memory allocation. This involves removing
    areas used by the kernel, but the logic missed some corner cases,
    which led to possible allocation in regions for which later memory
    access would cause a panic.

    The typical panic from this bug in GENERIC is at SVS startup:
    cpu_svs_init / uvm_pagealloc_strat / pagezero

    We fix the bug by adding logic for the missing cases of memory
    regions overlapping with the kernel. While there, add more #idef'ed
    debug output.
  module: src
  subject: 'CVS commit: src/sys/arch/x86/x86'
  unixtime: '1580262874'
  user: manu