go: runtime: fatal error: unknown caller pc

We’ve received a GC crash report from a Windows 10 user, running our Ethereum client built with Go 1.8.3 (amd64). We’ve never seen this error ever, so I doubt we can make a repro out of it, but here’s the crash logs if you can make heads or tails of it (you can find the full crash dump at https://github.com/ethereum/go-ethereum/issues/14725):

runtime: unexpected return pc for net.(*netFD).writeTo called from 0x80002000720013
fatal error: unknown caller pc

runtime stack:
runtime.throw(0xea8762, 0x11)
        C:/go/src/runtime/panic.go:596 +0x9c
runtime.gentraceback(0xffffffffffffffff, 0xc044903698, 0x0, 0xc0440544e0, 0x0, 0x0, 0x7fffffff, 0xf405e8, 0x45c2f978, 0x0, ...)
        C:/go/src/runtime/traceback.go:317 +0x13f8
runtime.copystack(0xc0440544e0, 0x2000, 0x0)
        C:/go/src/runtime/stack.go:932 +0x377
runtime.shrinkstack(0xc0440544e0)
        C:/go/src/runtime/stack.go:1186 +0x18c
runtime.scanstack(0xc0440544e0, 0xc042015228)
        C:/go/src/runtime/mgcmark.go:762 +0x386
runtime.scang(0xc0440544e0, 0xc042015228)
        C:/go/src/runtime/proc.go:866 +0x210
runtime.markroot.func1()
        C:/go/src/runtime/mgcmark.go:264 +0x7b
runtime.systemstack(0x45c2fda0)
        C:/go/src/runtime/asm_amd64.s:343 +0xb5
runtime.markroot(0xc042015228, 0xc00000006b)
        C:/go/src/runtime/mgcmark.go:269 +0x1e9
runtime.gcDrain(0xc042015228, 0x6)
        C:/go/src/runtime/mgcmark.go:1051 +0xcc
runtime.gcBgMarkWorker.func2()
        C:/go/src/runtime/mgc.go:1530 +0x101
runtime.systemstack(0xc0429f9700)
        C:/go/src/runtime/asm_amd64.s:327 +0x7e
runtime.mstart()
        C:/go/src/runtime/proc.go:1132

goroutine 19 [GC worker (idle)]:
runtime.systemstack_switch()
        C:/go/src/runtime/asm_amd64.s:281 fp=0xc042439f50 sp=0xc042439f48
runtime.gcBgMarkWorker(0xc042014000)
        C:/go/src/runtime/mgc.go:1537 +0x218 fp=0xc042439fd8 sp=0xc042439f50
runtime.goexit()
        C:/go/src/runtime/asm_amd64.s:2197 +0x1 fp=0xc042439fe0 sp=0xc042439fd8
created by runtime.gcBgMarkStartWorkers
        C:/go/src/runtime/mgc.go:1412 +0x9f