)]}'
{
  "commit": "28b166a700899a0f88b1cc283c449fb5bf72a635",
  "tree": "aebb983bd9f2aa6174f9ec8d3e658496c3231354",
  "parents": [
    "72d31053f62c4bc464c2783974926969614a8649"
  ],
  "author": {
    "name": "Aristeu Rozanski",
    "email": "aris@redhat.com",
    "time": "Mon Sep 22 13:14:13 2008 -0400"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@elte.hu",
    "time": "Mon Sep 22 19:48:18 2008 +0200"
  },
  "message": "x86, NMI watchdog: when booting with reset_devices, clear the performance counters\n\nP4s have a quirk that makes necessary to clear P4_CCCR_OVF bit on the CCCR\neverytime the PMI is triggered. When booting the kernel with reset_devices\n(more specific kdump case), the counters reach zero and the PMI will be\ngenerated. This is not a problem on other processors but on P4s, it\u0027ll\ncontinue to generate NMIs until that bit is cleared. Since there may be\nother users of the performance counters, clear and disable all of them\nwhen booting with reset_devices option.\n\nWe have a P4 box here that crashes because of this problem. Since the kdump\nkernel usually boots with only one processor active, the second logical\nunit won\u0027t be set up, therefore, MSR_P4_IQ_CCCR1 (and other performance\ncounter registers) won\u0027t be cleared and P4_CCCR_OVF may be still set because\nthe previous kernel was using this register. An NMI is triggered because of\nthe MSR_P4_IQ_CCCR1 right after the NMI delivery is enabled, triggering the\nrace fixed on my previous email.\n\nSigned-off-by: Aristeu Rozanski \u003caris@redhat.com\u003e\nAcked-by: Don Zickus \u003cdzickus@redhat.com\u003e\nAcked-by: Prarit Bhargava \u003cprarit@redhat.com\u003e\nAcked-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "05cc22dbd4ffdebff8738662c74fd954be8fd432",
      "old_mode": 33188,
      "old_path": "arch/x86/kernel/cpu/perfctr-watchdog.c",
      "new_id": "62c010063974e5caaa51e1dfd44ea8e54ad76154",
      "new_mode": 33188,
      "new_path": "arch/x86/kernel/cpu/perfctr-watchdog.c"
    }
  ]
}