runtime/pprof: TestMorestack failures on darwin/amd64

[bcmills]

As of CL 292229, the runtime/pprof tests are no longer skipped on macOS.
Unfortunately, they don't always pass, either:

Details

--- FAIL: TestMorestack (7.04s)
    pprof_test.go:274: uname -a: Darwin Gos-Mac-8.local 18.5.0 Darwin Kernel Version 18.5.0: Mon Mar 11 20:40:32 PDT 2019; root:xnu-4903.251.3~3/RELEASE_X86_64 x86_64
    pprof_test.go:393: total 15 CPU profile samples collected:
        4: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        9: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        1: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
    pprof_test.go:322: retrying with 200ms duration
    pprof_test.go:393: total 31 CPU profile samples collected:
        5: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        11: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        4: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        4: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        1: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        3: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        1: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
    pprof_test.go:322: retrying with 400ms duration
    pprof_test.go:393: total 62 CPU profile samples collected:
        1: 0x10578bd (runtime.findnull:436) 0x1059964 (runtime.gostringnocopy:462 runtime.funcname:862) 0x1065568 (runtime.isSystemGoroutine:1045) 0x1043c1e (runtime.goexit0:3391) 0x106d679 (runtime.mcall:313)
        
        33: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        6: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        3: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        3: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        9: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        2: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        2: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        2: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
    pprof_test.go:322: retrying with 800ms duration
    pprof_test.go:393: total 130 CPU profile samples collected:
        65: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        4: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        9: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        26: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        8: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        4: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        4: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        2: 0x10578bd (runtime.findnull:436) 0x1059964 (runtime.gostringnocopy:462 runtime.funcname:862) 0x1065568 (runtime.isSystemGoroutine:1045) 0x1043c1e (runtime.goexit0:3391) 0x106d679 (runtime.mcall:313)
        
        3: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        3: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        1: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
    pprof_test.go:322: retrying with 1.6s duration
    pprof_test.go:393: total 254 CPU profile samples collected:
        104: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        8: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        8: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        5: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        10: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        37: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        4: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        41: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        16: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        1: 0x105b138 (runtime.pthread_mutex_unlock:376) 0x1035152 (runtime.semawakeup:75) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        1: 0x104e248 (runtime.(*waitq).dequeueSudoG:614 runtime.selectgo:367) 0x1176344 (runtime/pprof.TestMorestack.func1:599) 0x11667a5 (runtime/pprof.testCPUProfile:313) 0x11688f4 (runtime/pprof.TestMorestack:591) 0x10e9d8e (testing.tRunner:1194)
        
        2: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x10426d8 (runtime.resetspinning:2987) 0x1042d78 (runtime.schedule:3143) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        6: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        4: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        6: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        1: 0x10578bd (runtime.findnull:436) 0x1059964 (runtime.gostringnocopy:462 runtime.funcname:862) 0x1065568 (runtime.isSystemGoroutine:1045) 0x1043c1e (runtime.goexit0:3391) 0x106d679 (runtime.mcall:313)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
    pprof_test.go:322: retrying with 3.2s duration
    pprof_test.go:393: total 507 CPU profile samples collected:
        69: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        255: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        16: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        68: 0x105b1f8 (runtime.pthread_cond_wait:390) 0x1034fec (runtime.semasleep:63) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        14: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        17: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x103d915 (runtime.ready:790) 0x103c597 (runtime.goready.func1:347) 0x106d708 (runtime.systemstack:358)
        
        9: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        12: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1035129 (runtime.semawakeup:70) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        13: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1042047 (runtime.findrunnable:2667) 0x1042d96 (runtime.schedule:3136) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        1: 0x10578bd (runtime.findnull:436) 0x1059964 (runtime.gostringnocopy:462 runtime.funcname:862) 0x1065568 (runtime.isSystemGoroutine:1045) 0x1043c1e (runtime.goexit0:3391) 0x106d679 (runtime.mcall:313)
        
        15: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        5: 0x105ab30 (runtime.usleep:226) 0x104a191 (runtime.runqgrab:5828) 0x104a296 (runtime.runqsteal:5863) 0x1041fc9 (runtime.findrunnable:2690) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        3: 0x105ac57 (runtime.nanotime1:253) 0x10431ab (runtime.nanotime:19 runtime.checkTimers:3216) 0x1041837 (runtime.findrunnable:2582) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        6: 0x11762eb (runtime/pprof.TestMorestack.func1:599) 0x11667a5 (runtime/pprof.testCPUProfile:313) 0x11688f4 (runtime/pprof.TestMorestack:591) 0x10e9d8e (testing.tRunner:1194)
        
        1: 0x105b138 (runtime.pthread_mutex_unlock:376) 0x1035152 (runtime.semawakeup:75) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x1045216 (runtime.newproc.func1:4004) 0x106d708 (runtime.systemstack:358)
        
        1: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x10426d8 (runtime.resetspinning:2987) 0x1042d78 (runtime.schedule:3143) 0x104331c (runtime.park_m:3285) 0x106d679 (runtime.mcall:313)
        
        1: 0x105b2b8 (runtime.pthread_cond_signal:404) 0x103516b (runtime.semawakeup:73) 0x100c87d (runtime.notewakeup:161) 0x1040798 (runtime.startm:2364) 0x1040c85 (runtime.wakep:2444) 0x10426d8 (runtime.resetspinning:2987) 0x1042d78 (runtime.schedule:3143) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
        1: 0x105b0d8 (runtime.pthread_mutex_lock:369) 0x1034fab (runtime.semasleep:42) 0x100c99a (runtime.notesleep:181) 0x103eef8 (runtime.mPark:1351) 0x1040511 (runtime.stopm:2268) 0x1041a4d (runtime.findrunnable:2927) 0x1042d96 (runtime.schedule:3136) 0x1043da9 (runtime.goexit0:3445) 0x106d679 (runtime.mcall:313)
        
    pprof_test.go:428: runtime.newstack,runtime/pprof.growstack: 0
    pprof_test.go:431: no samples in expected functions
    pprof_test.go:441: runtime.newstack,runtime/pprof.growstack has 0 samples out of 0, want at least 1, ideally 0
FAIL
FAIL	runtime/pprof	12.501s

2021-02-19T08:48:55-7764ee5/darwin-amd64-race
2021-02-19T01:22:14-87f425d/darwin-amd64-race
2021-02-19T00:41:47-5f2e24e/darwin-amd64-race
2021-02-19T00:41:41-ee7038f/darwin-amd64-race
2021-02-19T00:41:36-40765ff/darwin-amd64-10_14
2021-02-19T00:41:36-40765ff/darwin-amd64-race
2021-02-19T00:41:28-b445d6e/darwin-amd64-race

See previously #6047, #13841 (CC @rsc @cherrymui).

It's not obvious to me whether this is a lingering problem in the macOS platform, or a defect in either runtime/pprof or the test itself.

[bcmills]

This was mitigated on the darwin-amd64-race builder by CL 294071, but since there was also a failure on a non-race builder I suspect that it remains a (less severe) issue.

[bcmills]

Also mitigated on darwin-arm64-11_0-toothrot by CL 294409, but still flaking on other darwin:
2021-02-20T03:54:43-5b76343/darwin-amd64-10_12

[dmitshur]

This is a friendly ping since this is a release-blocking issue.

[cherrymui]

I'll take a look, maybe tomorrow.

[dmitshur]

@cherrymui A friendly ping on this again.

[gopherbot]

Change https://golang.org/cl/307730 mentions this issue: runtime/pprof: deflake TestMorestack

[bcmills]

Still a little flaky on arm64, it appears:
2021-06-15T10:13:08-abc56fd/darwin-arm64-11_0-toothrot
2021-04-30T00:32:42-303b194/darwin-arm64-11_0-toothrot

[bcmills]

Oop, this issue was for amd64. I'll open a separate one for arm64.