Btrfs: avoid possible use-after-free in clear_extent_bit()
authorLi Zefan <lizf@cn.fujitsu.com>
Mon, 12 Mar 2012 08:39:48 +0000 (16:39 +0800)
committerDavid Sterba <dsterba@suse.cz>
Wed, 18 Apr 2012 17:22:18 +0000 (19:22 +0200)
commitcdc6a3952558f00b1bc3b6401e1cf98797632fe2
treeb97cf714429b439c6887b2fe0acf9065e1d09f1f
parent8e52acf70459020d7e9e9fda25066be4da520943
Btrfs: avoid possible use-after-free in clear_extent_bit()

clear_extent_bit()
{
    next_node = rb_next(&state->rb_node);
    ...
    clear_state_bit(state);  <-- this may free next_node
    if (next_node) {
        state = rb_entry(next_node);
        ...
    }
}

clear_state_bit() calls merge_state() which may free the next node
of the passing extent_state, so clear_extent_bit() may end up
referencing freed memory.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
fs/btrfs/extent_io.c