testing fedora 27: tracepoints-section: build failed

[joe-lawrence]

Integration test results from PR #762

• Fedora release 27 (Twenty Seven)
• 4.13.13-300.fc27.x86_64
• gcc version 7.2.1 20170915 (Red Hat 7.2.1-2) (GCC)

  ERROR: tracepoints-section: build failed
  timer.o: changed function: run_timer_softirq
  timer.o: changed section .init.text not selected for inclusion
  timer.o: changed section .rela.init.text not selected for inclusion
  /root/kpatch.joe/kpatch-build/create-diff-object: unreconcilable difference
  meminfo.o: changed function: meminfo_proc_show

[joe-lawrence]

This one is weird. If I compare the disassembly:

vimdiff \
    <(objdump -D -j '.init.text' orig/kernel/time/timer.o) \
    <(objdump -D -j '.init.text' patched/kernel/time/timer.o)

The first thing I notice is that the order of the functions inside .init.text have been changed. If I rearrange the patched object file's output and then scrub both outputs of the unrelocated call / jump / etc references (ie, objdump lines like:

186:   e8 00 00 00 00          callq  18b <trace_event_define_fields_timer_expire_entry+0x56>

with generic "XYZ" offsets, then their assembly codes match up perfectly. So I think the patched object file's rearrangement modifies the '.rela.init.text' section as well because of this.

[joe-lawrence]

Fedora 27 is way EOL and we no longer carry tracepoints-section test in later (RHEL or upstream) integration tests. Closing.