DF-2631 build.log (summary; full untrimmed compiler logs were lost with the
QEMU disk reverts across the seven fix-kernel iterations)

[guest] images: plain copies of one newfs_hammer2 image (no forging):
  cp base.img m1.img; cp base.img m2.img; cp base.img m3.img
  md5(each) = 956fc18a70f6689a8669e21d372b4eb9

[guest] fix kernel iterations (all: cd /usr/src && make nativekernel &&
make installkernel -> BUILD_RC=0, "Kernel install ... completed"):
  #1 01:26:29  v1  (pfsfree kfree of xop_groups)          -> delayed panic
  #1 01:56:13  v2  (kfree removed)                         -> delayed panic
  #1 02:23:41  v3  (+ TEARDOWN guard, plain return)        -> umount stalls
  #1 02:52:56  v4  (+ feed-EOF on guard)                   -> 2630 soak clean
  #1 03:37:28  v5  (+ elapsed collect bound)               -> 11 s unwedge
  #1 04:08:55  v6  (+ SPMP exemption)                      -> crash @10 s knob
  #1 04:37:14  v7  (teardown-gated bound — did NOT unwedge)
  #1 05:10:55  final = v6 semantics (shipped fix.diff)     -> 61 s unwedge,
                                                              delayed panic