Comment 4 for bug 1415340

Exactly the same here.

Ubuntu 14.04.2
  LVM version: 2.02.98(2) (2012-10-15)
  Library version: 1.02.77 (2012-10-15)
  Driver version: 4.27.0

lvconvert --merge /dev/vg1/lv1_snap
(...)
lv1: Merged: 100,0%
Segmentation fault (core dumped)

Syslog:
Apr 26 18:20:03 vmhost1 kernel: [97102.219159] lvm[6560]: segfault at 28 ip 0000000000481a79 sp 00007ffdcb6849c0 error 4 in lvm[400000+e1000]
Apr 26 18:20:13 vmhost1 kernel: [97112.126617] lvconvert[6484]: segfault at 28 ip 0000000000481a79 sp 00007ffe68755c80 error 4 in lvm[400000+e1000]