)]}'
{
  "commit": "54481cf88bc59923ea30f2ca345a73c60155e901",
  "tree": "1965fad9a3a207a619b5506722208f93788210b8",
  "parents": [
    "ffe6e1da86d21d7855495b5a772c93f050258f6e"
  ],
  "author": {
    "name": "Suresh Siddha",
    "email": "suresh.b.siddha@intel.com",
    "time": "Thu Jun 19 09:41:22 2008 -0700"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@elte.hu",
    "time": "Fri Jun 20 13:26:18 2008 +0200"
  },
  "message": "x86: fix NULL pointer deref in __switch_to\n\nI am able to reproduce the oops reported by Simon in __switch_to() with\nlguest.\n\nMy debug showed that there is at least one lguest specific\nissue (which should be present in 2.6.25 and before aswell) and it got\nexposed with a kernel oops with the recent fpu dynamic allocation patches.\n\nIn addition to the previous possible scenario (with fpu_counter), in the\npresence of lguest, it is possible that the cpu\u0027s TS bit it still set and the\nlguest launcher task\u0027s thread_info has TS_USEDFPU still set.\n\nThis is because of the way the lguest launcher handling the guest\u0027s TS bit.\n(look at lguest_set_ts() in lguest_arch_run_guest()). This can result\nin a DNA fault while doing unlazy_fpu() in __switch_to(). This will\nend up causing a DNA fault in the context of new process thats\ngetting context switched in (as opossed to handling DNA fault in the context\nof lguest launcher/helper process).\n\nThis is wrong in both pre and post 2.6.25 kernels. In the recent\n2.6.26-rc series, this is showing up as NULL pointer dereferences or\nsleeping function called from atomic context(__switch_to()), as\nwe free and dynamically allocate the FPU context for the newly\ncreated threads. Older kernels might show some FPU corruption for processes\nrunning inside of lguest.\n\nWith the appended patch, my test system is running for more than 50 mins\nnow. So atleast some of your oops (hopefully all!) should get fixed.\nPlease give it a try. I will spend more time with this fix tomorrow.\n\nReported-by: Simon Holm Thøgersen \u003codie@cs.aau.dk\u003e\nReported-by: Patrick McHardy \u003ckaber@trash.net\u003e\nSigned-off-by: Suresh Siddha \u003csuresh.b.siddha@intel.com\u003e\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "5126d5d9ea0e8d8d97fa0eaf47ed22216329328b",
      "old_mode": 33188,
      "old_path": "drivers/lguest/x86/core.c",
      "new_id": "2e554a4ab33792dc7e92318cafe11a75e6c35246",
      "new_mode": 33188,
      "new_path": "drivers/lguest/x86/core.c"
    }
  ]
}