Comment 3 for bug 1548051

It's happening on 16.10 with the following Baloo packages:

# dpkg -l | grep baloo
ii baloo-kf5 5.28.0-0ubuntu1~ubuntu16.10~ppa1 amd64 framework for searching and managing metadata
ii baloo-utils 4:4.14.3-0ubuntu5 amd64 framework for searching and managing metadata.
ii libbaloocore4 4:4.14.3-0ubuntu5 amd64 Core funcationality for Baloo
ii libbaloofiles4 4:4.14.3-0ubuntu5 amd64 Files funcationality for Baloo
ii libbalooxapian4 4:4.14.3-0ubuntu5 amd64 Xapian funcationality for Baloo
ii libkf5baloo5 5.28.0-0ubuntu1~ubuntu16.10~ppa1 amd64 framework for searching and managing metadata core lib.
ii libkf5balooengine5 5.28.0-0ubuntu1~ubuntu16.10~ppa1 amd64 framework for searching and managing metadata plugins
ii libkf5baloowidgets-bin 4:16.04.3-0ubuntu1 amd64 Wigets for use with Baloo - binaries
ii libkf5baloowidgets5:amd64 4:16.04.3-0ubuntu1 amd64 Wigets for use with Baloo

strace on the baloo_file_extractor process that's using 100% cpu shows an infinite string of "brk" calls:
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000
brk(0x561794ccb000) = 0x561794ccb000
brk(0x561794e41000) = 0x561794e41000
brk(0x561794fb7000) = 0x561794fb7000

This is likely the cause of 2 complete lockups of my machines during the past 7 days.