runtime: `exit hook invoked panic` in `cmd/go.TestScript/cover_build_pkg_select`

[bcmills]

#!watchflakes
post <- `fatal error: internal error: exit hook invoked panic`

(Appears in logs matching #56197, but seen in other cover-related tests as well.)

(CC @thanm)

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- `fatal error: internal error: exit hook invoked panic`

2023-05-24 01:03 linux-amd64-longtest-race go@bdc5533f cmd/go.TestScript (log)

vcs-test.golang.org rerouted to http://127.0.0.1:41035
https://vcs-test.golang.org rerouted to https://127.0.0.1:33227
go test proxy running at GOPROXY=http://127.0.0.1:38877/mod
2023/05/24 02:04:37 http: TLS handshake error from 127.0.0.1:57136: EOF
2023/05/24 02:04:37 http: TLS handshake error from 127.0.0.1:57144: EOF
2023/05/24 02:04:37 http: TLS handshake error from 127.0.0.1:57152: EOF
--- FAIL: TestScript (1.15s)
    --- FAIL: TestScript/cover_build_pkg_select (5.72s)
        script_test.go:134: 2023-05-24T02:06:19Z
        script_test.go:136: $WORK=/workdir/tmp/cmd-go-test-763841144/tmpdir2860461067/cover_build_pkg_select3428911186
...
            fatal error: internal error: exit hook invoked panic

            goroutine 1 [running]:
            runtime.throw({0x52764e?, 0xc000014400?})
            	/workdir/go/src/runtime/panic.go:1077 +0x86 fp=0xc0000cbf10 sp=0xc0000cbee0 pc=0x457386
            runtime.runExitHooks(0x0)
            	/workdir/go/src/runtime/exithook.go:64 +0x18e fp=0xc0000cbf40 sp=0xc0000cbf10 pc=0x40ce6e
            runtime.main()
            	/workdir/go/src/runtime/proc.go:289 +0x5c5 fp=0xc0000cbfe0 sp=0xc0000cbf40 pc=0x45ba45
            runtime.goexit()
            	/workdir/go/src/runtime/asm_amd64.s:1650 +0x1 fp=0xc0000cbfe8 sp=0xc0000cbfe0 pc=0x4a42e1

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- `fatal error: internal error: exit hook invoked panic`

2023-07-10 19:19 darwin-amd64-longtest go@07ede7a5 runtime/coverage.TestCoverageApis (log)

--- FAIL: TestCoverageApis (37.85s)
    emitdata_test.go:52: atomic harness path is /tmp/buildlet/tmp/TestCoverageApis2135884621/001/build1/harness.exe
    emitdata_test.go:53: non-atomic harness path is /tmp/buildlet/tmp/TestCoverageApis2135884621/001/build2/harness.exe
    --- FAIL: TestCoverageApis/emitToNilWriter (0.38s)
        emitdata_test.go:166: running: /tmp/buildlet/tmp/TestCoverageApis2135884621/001/build1/harness.exe -tp emitToNilWriter -o /tmp/buildlet/tmp/TestCoverageApis2135884621/001/emitToNilWriter-edir-y with rdir=/tmp/buildlet/tmp/TestCoverageApis2135884621/001/emitToNilWriter-rdir-y and GOCOVERDIR=false
        emitdata_test.go:166: running: /tmp/buildlet/tmp/TestCoverageApis2135884621/001/build1/harness.exe -tp emitToNilWriter -o /tmp/buildlet/tmp/TestCoverageApis2135884621/001/emitToNilWriter-edir-x with rdir=/tmp/buildlet/tmp/TestCoverageApis2135884621/001/emitToNilWriter-rdir-x and GOCOVERDIR=true
        emitdata_test.go:329: I run last.
            fatal error: internal error: exit hook invoked panic

            goroutine 1 [running]:
            runtime.throw({0x117a958?, 0x127e438?})
            	/tmp/buildlet/go/src/runtime/panic.go:1077 +0xa5 fp=0xc00011df10 sp=0xc00011dee0 pc=0x106f285
            runtime.runExitHooks(0x0)
            	/tmp/buildlet/go/src/runtime/exithook.go:64 +0x1e5 fp=0xc00011df40 sp=0xc00011df10 pc=0x100f005
            runtime.main()
            	/tmp/buildlet/go/src/runtime/proc.go:289 +0x745 fp=0xc00011dfe0 sp=0xc00011df40 pc=0x10748a5
            runtime.goexit()
            	/tmp/buildlet/go/src/runtime/asm_amd64.s:1650 +0x1 fp=0xc00011dfe8 sp=0xc00011dfe0 pc=0x10d20c1

— watchflakes

[thanm]

Closing this out, hasn't happened in more than 9 months (we can always reopen if needed).