With

options libcfs cpu_npartitions=1 cpu_pattern="0[0-27]"

or just

options libcfs cpu_pattern="0[0-27]"

I get a crash when loading lnet.

2018-10-29T09:21:10.475881+01:00 b-an04 kernel: [ 2138.540432] LNet: HW NUMA nodes: 2, HW CPU cores: 28, npartitions: 1
2018-10-29T09:21:35.396884+01:00 b-an04 kernel: [ 2162.956139] BUG: unable to handle kernel paging request at ffffffffaaddd990
2018-10-29T09:21:35.396900+01:00 b-an04 kernel: [ 2162.963917] IP: native_queued_spin_lock_slowpath+0x16f/0x1a0
2018-10-29T09:21:35.396902+01:00 b-an04 kernel: [ 2162.970228] PGD 1c80e0e067 P4D 1c80e0e067 PUD 1c80e0f063 PMD 8000001c80a000e1

Without any options for libcfs loading lnet works as it should.

This worked whith MOFED 3.3 and Lustre 2.7