runtime: TestTimerFairness{2} occasionally hangs #7099
Description
Maybe it isn't so fair after all...
I saw 3 of these in an overnight run of all.bash. The test hangs and gets killed after
6 minutes.
SIGQUIT: quit^M
PC=0xf776342e^M
^M
^M
goroutine 1 [chan receive]:^M
testing.RunTests(0x8270818, 0x84a53e0, 0x4f, 0x4f, 0x1)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:472 +0x79d^M
testing.Main(0x8270818, 0x84a53e0, 0x4f, 0x4f, 0x84a6800, ...)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:403 +0x6b^M
main.main()^M
/tmp/go-build192147761/runtime/_test/_testmain.go:513 +0x83^M
^M
goroutine 60 [finalizer wait]:^M
runtime.park(0x8055240, 0x84a78b8, 0x84a668e)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc.c:1341 +0x65^M
runfinq()^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/mgc0.c:2486 +0x7b^M
runtime.goexit()^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc.c:1393^M
^M
goroutine 160309 [runnable]:^M
runtime_test.TestTimerFairness(0x188ef6c0)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:157 +0x173^M
testing.tRunner(0x188ef6c0, 0x84a56e0)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:391 +0x88^M
created by testing.RunTests^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:471 +0x782^M
^M
goroutine 160311 [running]:^M
goroutine running on other thread; stack unavailable^M
created by runtime_test.TestTimerFairness^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:152 +0xca^M
^M
goroutine 160310 [running]:^M
goroutine running on other thread; stack unavailable^M
created by runtime_test.TestTimerFairness^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:152 +0xca^M
eax 0xf0^M
ebx 0x84a97b4^M
ecx 0x0^M
edx 0x0^M
edi 0x0^M
esi 0x0^M
ebp 0x0^M
esp 0xffa7b5f4^M
eip 0xf776342e^M
eflags 0x296^M
cs 0x23^M
fs 0x0^M
gs 0x3f^M
*** Test killed with quit: ran too long (6m0s).^M
FAIL runtime 360.051s^M
SIGQUIT: quit^M
PC=0xf77d242e^M
^M
^M
goroutine 1 [chan receive]:^M
testing.RunTests(0x8270818, 0x84a53e0, 0x4f, 0x4f, 0x1)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:472 +0x79d^M
testing.Main(0x8270818, 0x84a53e0, 0x4f, 0x4f, 0x84a6800, ...)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:403 +0x6b^M
main.main()^M
/tmp/go-build861571265/runtime/_test/_testmain.go:513 +0x83^M
^M
goroutine 61 [finalizer wait]:^M
runtime.park(0x8055240, 0x84a78b8, 0x84a668e)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc.c:1341 +0x65^M
runfinq()^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/mgc0.c:2486 +0x7b^M
runtime.goexit()^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc.c:1393^M
^M
goroutine 240491 [running]:^M
goroutine running on other thread; stack unavailable^M
created by runtime_test.TestTimerFairness^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:152 +0xca^M
^M
goroutine 240494 [running]:^M
goroutine running on other thread; stack unavailable^M
created by runtime_test.TestTimerFairness2^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:183 +0xca^M
^M
goroutine 240492 [running]:^M
goroutine running on other thread; stack unavailable^M
created by runtime_test.TestTimerFairness^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:152 +0xca^M
^M
goroutine 240496 [running]:^M
goroutine running on other thread; stack unavailable^M
^M
goroutine 240493 [chan receive]:^M
runtime_test.TestTimerFairness2(0x187476c0)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/runtime/proc_test.go:186 +0x106^M
testing.tRunner(0x187476c0, 0x84a56ec)^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:391 +0x88^M
created by testing.RunTests^M
/usr/local/google/home/khr/sandbox/go-issue7083/src/pkg/testing/testing.go:471 +0x782^M
eax 0xf0^M
ebx 0x84a97b4^M
ecx 0x0^M
edx 0x0^M
edi 0x0^M
esi 0x0^M
ebp 0x0^M
esp 0xffaa7034^M
eip 0xf77d242e^M
eflags 0x296^M
cs 0x23^M
fs 0x0^M
gs 0x3f^M
*** Test killed with quit: ran too long (6m0s).^M
FAIL runtime 360.056s^M