With dm-mod compiled in kernel, lvm2 tools (vgscan and vgcreate in my case) causes segmentation faults.
* Note that when using dm-mod as a module, it works smoothly.
Steps to Reproduce:
1. Compile dm-mod in kernel (device mapper)
2. Emerge lvm2
3. Run vgscan
vgscan should returns volume groups found.
vgcreate should create a volume group.
I just went through the same thing on x86... would segfault when compiled in, but worked fine as a module.