go version devel +1757b5c Thu Dec 11 07:31:32 2014 +0000 linux/amd64

panic.log

runtime: g24: leftover defer argp=0xdeaddeaddeaddead pc=0x4872ea
	defer 0xc2081d1d40 argp=0xdeaddeaddeaddead pc=0x4872ea
	defer 0xc2081d1d00 argp=0xdeaddeaddeaddead pc=0x8f488c
	defer 0xc208296040 argp=0xdeaddeaddeaddead pc=0xb3c28e
fatal error: traceback has leftover defers

runtime stack:
runtime.gothrow(0x14aeef0, 0x1d)
	/home/mattyw/go/src/runtime/panic.go:507 +0x98
runtime.gentraceback(0x42e348, 0xc208193c20, 0x0, 0xc2080e79e0, 0x0, 0x0, 0x7fffffff, 0x16a0af0, 0x0, 0x0, ...)
	/home/mattyw/go/src/runtime/traceback.go:446 +0x709
runtime.scanstack(0xc2080e79e0)
	/home/mattyw/go/src/runtime/mgc.go:956 +0x214
runtime.gcphasework(0xc2080e79e0)
	/home/mattyw/go/src/runtime/mgc.go:1062 +0x80
runtime.stopg(0xc2080e79e0, 0x4)
	/home/mattyw/go/src/runtime/proc1.go:444 +0x91
runtime.markroot(0xc20800a070, 0xc)
	/home/mattyw/go/src/runtime/mgc.go:692 +0x161
runtime.parfordo(0xc20800a070)
	/home/mattyw/go/src/runtime/parfor.go:69 +0x12f
runtime.gcscan_m()
	/home/mattyw/go/src/runtime/mgc.go:1798 +0x15c
runtime.systemstack(0xc208010000)
	/home/mattyw/go/src/runtime/asm_amd64.s:244 +0x71
runtime.mstart()
	/home/mattyw/go/src/runtime/proc1.go:720

goroutine 2 [garbage collection scan, 2 minutes]:
runtime.systemstack_switch()
	/home/mattyw/go/src/runtime/asm_amd64.s:199 fp=0xc208018768 sp=0xc208018760
runtime.gogc(0x1)
	/home/mattyw/go/src/runtime/malloc.go:481 +0x13d fp=0xc2080187c0 sp=0xc208018768
runtime.forcegchelper()
	/home/mattyw/go/src/runtime/proc.go:120 +0x10e fp=0xc2080187e0 sp=0xc2080187c0
runtime.goexit()
	/home/mattyw/go/src/runtime/asm_amd64.s:2402 +0x1 fp=0xc2080187e8 sp=0xc2080187e0
created by runtime.init·4
	/home/mattyw/go/src/runtime/proc.go:103 +0x25