The test for presence of tcp_tw_recycle is broken and always succeeds. This didn't matter as long as the file was always present. However, it is apparently gone since Linux 4.12.
Created attachment 15224 [details] Patch for 4.9 and 4.10
Hi Karolin, This is ready for v4-9 and v4-10. Thanks.
(In reply to Amitay Isaacs from comment #2) Pushed to autobuild-v4-{10,9}-test.
(In reply to Karolin Seeger from comment #3) Pushed to both branches. Closing out bug report. Thanks!