perf-4.8.0-rc3: Segmentation fault

[Alexey Dobriyan]

I profiled kernel allmodconfig build (don't ask) and perf tui reliably
segfaults when trying to enter annotation mode for any of the
individual functions. It segfaults immediately before even showing
menu with choices.

perf: Segmentation fault
-------- backtrace --------
perf[0x5451fb]
/lib64/libc.so.6(+0x33290)[0x7fcec0a80290]
perf(__map__is_kernel+0x26)[0x4bbcd6]
perf[0x54287c]
perf(perf_evlist__tui_browse_hists+0x94)[0x543e84]
perf(cmd_report+0x1a34)[0x434884]
perf[0x478471]
perf(main+0x6c6)[0x4237e6]
/lib64/libc.so.6(__libc_start_main+0xf0)[0x7fcec0a6d630]
perf(_start+0x29)[0x4238e9]

Steps to reproduce:
    rm -rf ../xxx
    mkdir ../xxx
    make O=../xxx ARCH=x86_64 allmodconfig
    perf record -e cycles make O=../xxx -k -j5
    perf report

perf.data is 1.23 GB long , so be prepared.