Starting a bunch of goroutines...
fatal error: runtime.SetFinalizer: finalizer already set

runtime stack:
runtime.SetFinalizer.func2()
        /home/derek/go/src/github.com/golang/go/src/runtime/mfinal.go:375 +0x73

goroutine 32446951 [running]:
runtime.systemstack_switch()
        /home/derek/go/src/github.com/golang/go/src/runtime/asm_amd64.s:252 fp=0xc4202b7bb8 sp=0xc4202b7bb0
runtime.SetFinalizer(0x4a5680, 0xc420152b20, 0x4a4980, 0x4c86b0)
        /home/derek/go/src/github.com/golang/go/src/runtime/mfinal.go:377 +0x250 fp=0xc4202b7c98 sp=0xc4202b7bb8
os.NewFile(0xb, 0x4be30a, 0x9, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:57 +0xe4 fp=0xc4202b7cd0 sp=0xc4202b7c98
os.OpenFile(0x4be30a, 0x9, 0x1, 0xc400000000, 0x1, 0x8005194b0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:123 +0xf2 fp=0xc4202b7d38 sp=0xc4202b7cd0
os/exec.(*Cmd).writerDescriptor(0xc4203ed900, 0x0, 0x0, 0x0, 0x0, 0xc4202fc8b0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:217 +0x539 fp=0xc4202b7dd8 sp=0xc4202b7d38
os/exec.(*Cmd).stderr(0xc4203ed900, 0xc4202fc8a8, 0x1, 0x1)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:212 +0x44 fp=0xc4202b7e20 sp=0xc4202b7dd8
os/exec.(*Cmd).Start(0xc4203ed900, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:326 +0xd6 fp=0xc4202b7f68 sp=0xc4202b7e20
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e fp=0xc4202b7fb8 sp=0xc4202b7f68
runtime.goexit()
        /home/derek/go/src/github.com/golang/go/src/runtime/asm_amd64.s:2058 +0x1 fp=0xc4202b7fc0 sp=0xc4202b7fb8
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 1 [chan receive]:
main.main()
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:62 +0x181

goroutine 32446944 [runnable]:
syscall.Syscall(0x5, 0xc420452720, 0x100000, 0x0, 0xf, 0x0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/asm_freebsd_amd64.s:21 +0x5
syscall.Open(0x4be30a, 0x9, 0x100000, 0x0, 0x0, 0x42b2be, 0xc42001950c)
        /home/derek/go/src/github.com/golang/go/src/syscall/zsyscall_freebsd_amd64.go:823 +0x90
os.OpenFile(0x4be30a, 0x9, 0x0, 0x0, 0xc420452710, 0xc420452710, 0xc4203a9dc8)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:97 +0x9a
os.Open(0x4be30a, 0x9, 0x0, 0x0, 0x4660bf)
        /home/derek/go/src/github.com/golang/go/src/os/file.go:246 +0x3c
os/exec.(*Cmd).stdin(0xc42030e780, 0xc4203a9d90, 0x16d, 0x51aea0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:172 +0x511
os/exec.(*Cmd).Start(0xc42030e780, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:326 +0xd6
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446927 [runnable]:
syscall.Syscall(0x6, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/asm_freebsd_amd64.s:21 +0x5
syscall.Close(0x3, 0xc420107bd8, 0x8)
        /home/derek/go/src/github.com/golang/go/src/syscall/zsyscall_freebsd_amd64.go:384 +0x40
syscall.forkExec(0xc42014f030, 0xd, 0xc42014ef80, 0x1, 0x1, 0xc420107d70, 0xc42015a000, 0x4c7764, 0x800519000)
        /home/derek/go/src/github.com/golang/go/src/syscall/exec_unix.go:203 +0x3c4
syscall.StartProcess(0xc42014f030, 0xd, 0xc42014ef80, 0x1, 0x1, 0xc420107d70, 0x2, 0x4, 0xc420116d00, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/exec_unix.go:240 +0x53
os.startProcess(0xc42014f030, 0xd, 0xc42014ef80, 0x1, 0x1, 0xc420107f08, 0xc4203a2c60, 0x11, 0x11)
        /home/derek/go/src/github.com/golang/go/src/os/exec_posix.go:45 +0x186
os.StartProcess(0xc42014f030, 0xd, 0xc42014ef80, 0x1, 0x1, 0xc420107f08, 0x0, 0x0, 0xc42014f030)
        /home/derek/go/src/github.com/golang/go/src/os/doc.go:28 +0x53
os/exec.(*Cmd).Start(0xc4200b3540, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:342 +0x393
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446943 [runnable]:
syscall.Getenv(0x4bdac5, 0x4, 0x0, 0x0, 0xffffffffffffff00)
        /home/derek/go/src/github.com/golang/go/src/syscall/env_unix.go:80 +0xcd
os.Getenv(0x4bdac5, 0x4, 0x4bd910, 0x1)
        /home/derek/go/src/github.com/golang/go/src/os/env.go:80 +0x2b
os/exec.LookPath(0x4bdb4d, 0x4, 0x4bdb4d, 0x4, 0x1, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/lp_unix.go:46 +0x88
os/exec.Command(0x4bdb4d, 0x4, 0x0, 0x0, 0x0, 0xc4204db7c0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:133 +0x1d1
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:38 +0x4b
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446940 [runnable]:
runtime.SetFinalizer(0x4a5680, 0xc420310fc0, 0x4a4980, 0x4c86b0)
        /home/derek/go/src/github.com/golang/go/src/runtime/mfinal.go:265
os.NewFile(0xa, 0x4be30a, 0x9, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:57 +0xe4
os.OpenFile(0x4be30a, 0x9, 0x0, 0x0, 0xc4203a1760, 0xc4203a1760, 0xc4201559a8)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:123 +0xf2
os.Open(0x4be30a, 0x9, 0x0, 0x0, 0x4660bf)
        /home/derek/go/src/github.com/golang/go/src/os/file.go:246 +0x3c
os/exec.(*Cmd).stdin(0xc42039f2c0, 0xc420155970, 0x16d, 0x51aea0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:172 +0x511
os/exec.(*Cmd).Start(0xc42039f2c0, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:326 +0xd6
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446978 [runnable]:
syscall.Syscall(0x6, 0x5, 0x0, 0x0, 0x0, 0x0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/asm_freebsd_amd64.s:21 +0x5
syscall.Close(0x5, 0xc420092bd8, 0x8)
        /home/derek/go/src/github.com/golang/go/src/syscall/zsyscall_freebsd_amd64.go:384 +0x40
syscall.forkExec(0xc4200bbf70, 0xd, 0xc4200bbec0, 0x1, 0x1, 0xc420092d70, 0xc42002a800, 0x4c7764, 0x800519960)
        /home/derek/go/src/github.com/golang/go/src/syscall/exec_unix.go:203 +0x3c4
syscall.StartProcess(0xc4200bbf70, 0xd, 0xc4200bbec0, 0x1, 0x1, 0xc420092d70, 0x2, 0x4, 0xc420366820, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/exec_unix.go:240 +0x53
os.startProcess(0xc4200bbf70, 0xd, 0xc4200bbec0, 0x1, 0x1, 0xc420092f08, 0xc42036f440, 0x11, 0x11)
        /home/derek/go/src/github.com/golang/go/src/os/exec_posix.go:45 +0x186
os.StartProcess(0xc4200bbf70, 0xd, 0xc4200bbec0, 0x1, 0x1, 0xc420092f08, 0x0, 0x0, 0xc4200bbf70)
        /home/derek/go/src/github.com/golang/go/src/os/doc.go:28 +0x53
os/exec.(*Cmd).Start(0xc420517e00, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:342 +0x393
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446941 [runnable]:
strings.Join(0xc42049d6d0, 0x2, 0x2, 0x4bd910, 0x1, 0xc4203f9a20, 0x45b41f)
        /home/derek/go/src/github.com/golang/go/src/strings/strings.go:362 +0x272
path/filepath.join(0xc42049d6d0, 0x2, 0x2, 0x51a1a0, 0xc4203cfef0)
        /home/derek/go/src/github.com/golang/go/src/path/filepath/path_unix.go:42 +0x98
path/filepath.Join(0xc42049d6d0, 0x2, 0x2, 0xc4203cfef0, 0xa)
        /home/derek/go/src/github.com/golang/go/src/path/filepath/path.go:206 +0x35
os/exec.LookPath(0x4bdb4d, 0x4, 0x4bdb4d, 0x4, 0x1, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/lp_unix.go:52 +0x156
os/exec.Command(0x4bdb4d, 0x4, 0x0, 0x0, 0x0, 0xc420497180)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:133 +0x1d1
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:38 +0x4b
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3

goroutine 32446942 [runnable]:
syscall.Syscall(0x5, 0xc4202901e0, 0x100001, 0x0, 0xe, 0x0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/syscall/asm_freebsd_amd64.s:21 +0x5
syscall.Open(0x4be30a, 0x9, 0x100001, 0x0, 0xc420462988, 0x8, 0x8)
        /home/derek/go/src/github.com/golang/go/src/syscall/zsyscall_freebsd_amd64.go:823 +0x90
os.OpenFile(0x4be30a, 0x9, 0x1, 0x800000000, 0x0, 0x0, 0x459c5b)
        /home/derek/go/src/github.com/golang/go/src/os/file_unix.go:97 +0x9a
os/exec.(*Cmd).writerDescriptor(0xc4204583c0, 0x0, 0x0, 0x0, 0x0, 0x1)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:217 +0x539
os/exec.(*Cmd).stdout(0xc4204583c0, 0x0, 0x0, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:205 +0x33
os/exec.(*Cmd).Start(0xc4204583c0, 0x4, 0x0)
        /home/derek/go/src/github.com/golang/go/src/os/exec/exec.go:326 +0xd6
main.run(0xc42006e060)
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:39 +0x5e
created by main.main
        /home/derek/dev/crashgo/src/cmd/crashgo/main.go:63 +0x1a3