)]}'
{
  "commit": "6dd9ad7df2019b1e33a372a501907db293ebcd0d",
  "tree": "1a07cfde1f3ea94b3f5f62e688d21668ff7831e4",
  "parents": [
    "334c2b0b8b2ab186fa198413386cba41fffcb4f2"
  ],
  "author": {
    "name": "Tejun Heo",
    "email": "tj@kernel.org",
    "time": "Thu Nov 03 18:52:11 2011 +0100"
  },
  "committer": {
    "name": "Jens Axboe",
    "email": "axboe@kernel.dk",
    "time": "Thu Nov 03 18:52:11 2011 +0100"
  },
  "message": "block: don\u0027t call blk_drain_queue() if elevator is not up\n\nblk_cleanup_queue() may be called before elevator is set up on a\nqueue which triggers the following oops.\n\n BUG: unable to handle kernel NULL pointer dereference at           (null)\n IP: [\u003cffffffff8125a69c\u003e] elv_drain_elevator+0x1c/0x70\n ...\n Pid: 830, comm: kworker/0:2 Not tainted 3.1.0-next-20111025_64+ #1590\n Bochs Bochs\n RIP: 0010:[\u003cffffffff8125a69c\u003e]  [\u003cffffffff8125a69c\u003e] elv_drain_elevator+0x1c/0x70\n ...\n Call Trace:\n  [\u003cffffffff8125da92\u003e] blk_drain_queue+0x42/0x70\n  [\u003cffffffff8125db90\u003e] blk_cleanup_queue+0xd0/0x1c0\n  [\u003cffffffff81469640\u003e] md_free+0x50/0x70\n  [\u003cffffffff8126f43b\u003e] kobject_release+0x8b/0x1d0\n  [\u003cffffffff81270d56\u003e] kref_put+0x36/0xa0\n  [\u003cffffffff8126f2b7\u003e] kobject_put+0x27/0x60\n  [\u003cffffffff814693af\u003e] mddev_delayed_delete+0x2f/0x40\n  [\u003cffffffff81083450\u003e] process_one_work+0x100/0x3b0\n  [\u003cffffffff8108527f\u003e] worker_thread+0x15f/0x3a0\n  [\u003cffffffff81089937\u003e] kthread+0x87/0x90\n  [\u003cffffffff81621834\u003e] kernel_thread_helper+0x4/0x10\n\nFix it by making blk_cleanup_queue() check whether q-\u003eelevator is set\nup before invoking blk_drain_queue.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nReported-and-tested-by: Jiri Slaby \u003cjslaby@suse.cz\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "f65871116404b3fd1471ffc6243bd6034d23e4cc",
      "old_mode": 33188,
      "old_path": "block/blk-core.c",
      "new_id": "f43c8a5840ae488131dbf395d5eaf96e2fea876d",
      "new_mode": 33188,
      "new_path": "block/blk-core.c"
    }
  ]
}