# Generally, hchan must be acquired before gscan. But in one case,
# where we suspend a G and then shrink its stack, syncadjustsudogs
# can acquire hchan locks while holding gscan. To allow this case,
# we use hchanLeaf instead of hchan.
gscan < hchanLeaf;

# Write barrier
defer,
  gscan,
  mspanSpecial,
  pollCache,
  sudog,
  timer
# Anything that can have write barriers can acquire WB.