net/http/pprof: timeout in `TestDeltaProfile` with running `mutexHog` goroutine

[gopherbot]

#!watchflakes
post <- pkg == "net/http/pprof" && log ~ `\s+TestDeltaProfile \(\d+m\d+s\)` && log ~ `goroutine \d+ .*\[running\]:\n(?:\s*.+\n)*created by net/http/pprof\.mutexHog`

Issue created automatically to collect these failures.

Example (log):

panic: test timed out after 15m0s
running tests:
    TestDeltaProfile (14m56s)

goroutine 422 gp=0xc00009ba00 m=4 mp=0xc000069508 [running]:
panic({0x13839c0?, 0xc000206060?})
    C:/workdir/go/src/runtime/panic.go:779 +0x158 fp=0xc0000d5f10 sp=0xc0000d5e60 pc=0x10ca958
testing.(*M).startAlarm.func1()
    C:/workdir/go/src/testing/testing.go:2351 +0x374 fp=0xc0000d5fe0 sp=0xc0000d5f10 pc=0x1189494
runtime.goexit({})
...
net.(*TCPConn).Read(0x0?, {0xc000202041?, 0x0?, 0x0?})
    <autogenerated>:1 +0x25 fp=0xc0002d7f80 sp=0xc0002d7f50 pc=0x126e6e5
net/http.(*connReader).backgroundRead(0xc000202030)
    C:/workdir/go/src/net/http/server.go:681 +0x37 fp=0xc0002d7fc8 sp=0xc0002d7f80 pc=0x132e837
net/http.(*connReader).startBackgroundRead.gowrap2()
    C:/workdir/go/src/net/http/server.go:677 +0x25 fp=0xc0002d7fe0 sp=0xc0002d7fc8 pc=0x132e765
runtime.goexit({})
    C:/workdir/go/src/runtime/asm_amd64.s:1695 +0x1 fp=0xc0002d7fe8 sp=0xc0002d7fe0 pc=0x10ffae1
created by net/http.(*connReader).startBackgroundRead in goroutine 98
    C:/workdir/go/src/net/http/server.go:677 +0xba

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "net/http/pprof" && test == ""

2023-11-21 21:29 windows-amd64-longtest go@90ba4452 net/http/pprof (log)

panic: test timed out after 15m0s running tests: TestDeltaProfile (14m56s) goroutine 422 gp=0xc00009ba00 m=4 mp=0xc000069508 [running]: panic({0x13839c0?, 0xc000206060?}) C:/workdir/go/src/runtime/panic.go:779 +0x158 fp=0xc0000d5f10 sp=0xc0000d5e60 pc=0x10ca958 testing.(*M).startAlarm.func1() C:/workdir/go/src/testing/testing.go:2351 +0x374 fp=0xc0000d5fe0 sp=0xc0000d5f10 pc=0x1189494 runtime.goexit({}) ... net.(*TCPConn).Read(0x0?, {0xc000202041?, 0x0?, 0x0?}) :1 +0x25 fp=0xc0002d7f80 sp=0xc0002d7f50 pc=0x126e6e5 net/http.(*connReader).backgroundRead(0xc000202030) C:/workdir/go/src/net/http/server.go:681 +0x37 fp=0xc0002d7fc8 sp=0xc0002d7f80 pc=0x132e837 net/http.(*connReader).startBackgroundRead.gowrap2() C:/workdir/go/src/net/http/server.go:677 +0x25 fp=0xc0002d7fe0 sp=0xc0002d7fc8 pc=0x132e765 runtime.goexit({}) C:/workdir/go/src/runtime/asm_amd64.s:1695 +0x1 fp=0xc0002d7fe8 sp=0xc0002d7fe0 pc=0x10ffae1 created by net/http.(*connReader).startBackgroundRead in goroutine 98 C:/workdir/go/src/net/http/server.go:677 +0xba

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- pkg == "net/http/pprof" && log ~ `\s+TestDeltaProfile \(\d+m\d+s\)` && log ~ `goroutine \d+ .*\[running\]:\n(?:\s*.+\n)*created by net/http/pprof\.mutexHog`

2023-12-18 17:42 windows-386-2016 go@8e3930f2 net/http/pprof (log)

panic: test timed out after 3m0s running tests: TestDeltaProfile (2m56s) goroutine 419 gp=0x25b0008 m=8 mp=0x2080b08 [running]: panic({0xee9e80, 0x25b2028}) C:/workdir/go/src/runtime/panic.go:779 +0x123 fp=0x2262f84 sp=0x2262f30 pc=0xbfcc33 testing.(*M).startAlarm.func1() C:/workdir/go/src/testing/testing.go:2366 +0x38a fp=0x2262ff0 sp=0x2262f84 pc=0xcc4e9a runtime.goexit({}) ... sync.(*Mutex).Lock(0x22520e0) C:/workdir/go/src/sync/mutex.go:90 +0x4a fp=0x2267f7c sp=0x2267f68 pc=0xc3f8ba net/http/pprof.mutexHog2(0x22520e0, 0x22520e8, {0xc1583f7bdfb29bd8, 0x12cb3775d, 0x1194500}, 0x1312d00) C:/workdir/go/src/net/http/pprof/pprof_test.go:129 +0x88 fp=0x2267fb0 sp=0x2267f7c pc=0xebe9f8 net/http/pprof.mutexHog.func1() C:/workdir/go/src/net/http/pprof/pprof_test.go:151 +0x99 fp=0x2267ff0 sp=0x2267fb0 pc=0xebecb9 runtime.goexit({}) C:/workdir/go/src/runtime/asm_386.s:1363 +0x1 fp=0x2267ff4 sp=0x2267ff0 pc=0xc35c61 created by net/http/pprof.mutexHog in goroutine 66 C:/workdir/go/src/net/http/pprof/pprof_test.go:149 +0x9d

— watchflakes