Stack dump of exec-deadlock.go when it has deadlocked.

exec-deadlock.stack

Compile environment: CGO_ENABLED=0
Compiled with go1.18.1 .tar.gz release for darwin/amd64
Run on darwin/amd64 (macOS 11.6.5)

Output obtained from a dlv debugging session:
============================================================
(dlv) goroutines
  Goroutine 1 - User: /opt/go1.18.1/src/runtime/os_darwin.go:348 syscall.runtime_BeforeExec (0x1058dd3)
  Goroutine 2 - User: /opt/go1.18.1/src/runtime/proc.go:362 runtime.gopark (0x1031fb6) [force gc (idle)]
  Goroutine 3 - User: /opt/go1.18.1/src/runtime/proc.go:362 runtime.gopark (0x1031fb6) [finalizer wait]
  Goroutine 4 - User: /opt/go1.18.1/src/runtime/proc.go:362 runtime.gopark (0x1031fb6) [select]
  Goroutine 17 - User: /opt/go1.18.1/src/runtime/proc.go:362 runtime.gopark (0x1031fb6) [GC sweep wait]
  Goroutine 18 - User: /opt/go1.18.1/src/runtime/proc.go:362 runtime.gopark (0x1031fb6) [GC scavenge wait]
  Goroutine 33 - User: /opt/go1.18.1/src/runtime/sigqueue.go:148 os/signal.signal_recv (0x1059768)
[7 goroutines]
(dlv) goroutine 1 bt
0  0x000000000105ab80 in runtime.systemstack_switch
   at /opt/go1.18.1/src/runtime/asm_amd64.s:436
1  0x000000000104de46 in runtime.libcCall
   at /opt/go1.18.1/src/runtime/sys_libc.go:48
2  0x000000000104d5cc in runtime.usleep
   at /opt/go1.18.1/src/runtime/sys_darwin.go:248
3  0x0000000001058dd3 in runtime.osyield
   at /opt/go1.18.1/src/runtime/os_darwin.go:348
4  0x0000000001058dd3 in syscall.runtime_BeforeExec
   at /opt/go1.18.1/src/runtime/proc.go:4021
5  0x0000000001076165 in syscall.Exec
   at /opt/go1.18.1/src/syscall/exec_unix.go:283
6  0x000000000108eddb in main.main
   at ./exec-deadlock.go:12
7  0x0000000001031bf2 in runtime.main
   at /opt/go1.18.1/src/runtime/proc.go:250
8  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 2 bt
0  0x0000000001031fb6 in runtime.gopark
   at /opt/go1.18.1/src/runtime/proc.go:362
1  0x0000000001031e4d in runtime.goparkunlock
   at /opt/go1.18.1/src/runtime/proc.go:367
2  0x0000000001031e4d in runtime.forcegchelper
   at /opt/go1.18.1/src/runtime/proc.go:301
3  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 3 bt
0  0x0000000001031fb6 in runtime.gopark
   at /opt/go1.18.1/src/runtime/proc.go:362
1  0x0000000001014e73 in runtime.goparkunlock
   at /opt/go1.18.1/src/runtime/proc.go:367
2  0x0000000001014e73 in runtime.runfinq
   at /opt/go1.18.1/src/runtime/mfinal.go:177
3  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 4 bt
0  0x0000000001031fb6 in runtime.gopark
   at /opt/go1.18.1/src/runtime/proc.go:362
1  0x00000000010411f2 in runtime.selectgo
   at /opt/go1.18.1/src/runtime/select.go:328
2  0x0000000001045332 in runtime.ensureSigM.func1
   at /opt/go1.18.1/src/runtime/signal_unix.go:973
3  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 17 bt
0  0x0000000001031fb6 in runtime.gopark
   at /opt/go1.18.1/src/runtime/proc.go:362
1  0x000000000101ffee in runtime.goparkunlock
   at /opt/go1.18.1/src/runtime/proc.go:367
2  0x000000000101ffee in runtime.bgsweep
   at /opt/go1.18.1/src/runtime/mgcsweep.go:278
3  0x0000000001015dc6 in runtime.gcenable.func1
   at /opt/go1.18.1/src/runtime/mgc.go:177
4  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 18 bt
0  0x0000000001031fb6 in runtime.gopark
   at /opt/go1.18.1/src/runtime/proc.go:362
1  0x000000000101dc6c in runtime.goparkunlock
   at /opt/go1.18.1/src/runtime/proc.go:367
2  0x000000000101dc6c in runtime.bgscavenge
   at /opt/go1.18.1/src/runtime/mgcscavenge.go:272
3  0x0000000001015d66 in runtime.gcenable.func2
   at /opt/go1.18.1/src/runtime/mgc.go:178
4  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571
(dlv) goroutine 33 bt
0  0x000000000105ab80 in runtime.systemstack_switch
   at /opt/go1.18.1/src/runtime/asm_amd64.s:436
1  0x000000000104de46 in runtime.libcCall
   at /opt/go1.18.1/src/runtime/sys_libc.go:48
2  0x000000000104d4b4 in runtime.read
   at /opt/go1.18.1/src/runtime/sys_darwin.go:215
3  0x000000000102c8fe in runtime.sigNoteSleep
   at /opt/go1.18.1/src/runtime/os_darwin.go:124
4  0x0000000001059768 in os/signal.signal_recv
   at /opt/go1.18.1/src/runtime/sigqueue.go:148
5  0x000000000108ecb9 in os/signal.loop
   at /opt/go1.18.1/src/os/signal/signal_unix.go:23
6  0x000000000105cc81 in runtime.goexit
   at /opt/go1.18.1/src/runtime/asm_amd64.s:1571