Thread local storage define in assembly

Question

I define a thread local storage in assembly,

  " .LOCALMAP:\n"
  "   .section .tbss,\"awT\",@nobits\n"
  "   .type  LOCALMAP,@object\n"
  "   .size LOCALMAP,8\n"
  "   .zero 8\n"

as get errors: "attempt to store non-empty string in section `.tbss'" ? why those error occurs?

btw,i creat thread local storage in assembly into afl afl-as.h for some use.