)]}'
{
  "commit": "1ce82b69e96c838d007f316b8347b911fdfa9842",
  "tree": "be34e7c88a2544e620638834c8120b14b277d64a",
  "parents": [
    "2919bfd0758257c469abef8c26c3e516bbebb851"
  ],
  "author": {
    "name": "Hugh Dickins",
    "email": "hughd@google.com",
    "time": "Thu Jan 13 15:47:30 2011 -0800"
  },
  "committer": {
    "name": "Linus Torvalds",
    "email": "torvalds@linux-foundation.org",
    "time": "Thu Jan 13 17:32:49 2011 -0800"
  },
  "message": "mm: fix migration hangs on anon_vma lock\n\nIncreased usage of page migration in mmotm reveals that the anon_vma\nlocking in unmap_and_move() has been deficient since 2.6.36 (or even\nearlier).  Review at the time of f18194275c39835cb84563500995e0d503a32d9a\n(\"mm: fix hang on anon_vma-\u003eroot-\u003elock\") missed the issue here: the\nanon_vma to which we get a reference may already have been freed back to\nits slab (it is in use when we check page_mapped, but that can change),\nand so its anon_vma-\u003eroot may be switched at any moment by reuse in\nanon_vma_prepare.\n\nPerhaps we could fix that with a get_anon_vma_unless_zero(), but let\u0027s\nnot: just rely on page_lock_anon_vma() to do all the hard thinking for us,\nthen we don\u0027t need any rcu read locking over here.\n\nIn removing the rcu_unlock label: since PageAnon is a bit in\npage-\u003emapping, it\u0027s impossible for a !page-\u003emapping page to be anon; but\ninsert VM_BUG_ON in case the implementation ever changes.\n\n[akpm@linux-foundation.org: coding-style fixes]\nSigned-off-by: Hugh Dickins \u003chughd@google.com\u003e\nReviewed-by: Mel Gorman \u003cmel@csn.ul.ie\u003e\nReviewed-by: Rik van Riel \u003criel@redhat.com\u003e\nCc: Naoya Horiguchi \u003cn-horiguchi@ah.jp.nec.com\u003e\nCc: \"Jun\u0027ichi Nomura\" \u003cj-nomura@ce.jp.nec.com\u003e\nCc: Andi Kleen \u003cak@linux.intel.com\u003e\nCc: \u003cstable@kernel.org\u003e [2.6.37, 2.6.36]\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "89a6bc8cd3072df5df12e9a52b952e33b5231db2",
      "old_mode": 33188,
      "old_path": "mm/migrate.c",
      "new_id": "a20cf12edededf14c4a47a437d2e46252b9504f4",
      "new_mode": 33188,
      "new_path": "mm/migrate.c"
    }
  ]
}