cmd/link, runtime: signal causes 'fatal: morestack on g0' on darwin/amd64

[josharian]

Using tip at 8cd0094 on darwin/amd64.

Run go tool compile -S x.go | head, for any x.go.

Result:

$ go tool compile -S x.go | head -n 10
"".main STEXT size=319 args=0x0 locals=0xf0
	0x0000 00000 (x.go:8)	TEXT	"".main(SB), $240-0
	0x0000 00000 (x.go:8)	MOVQ	(TLS), CX
	0x0009 00009 (x.go:8)	LEAQ	-112(SP), AX
	0x000e 00014 (x.go:8)	CMPQ	AX, 16(CX)
	0x0012 00018 (x.go:8)	JLS	309
	0x0018 00024 (x.go:8)	SUBQ	$240, SP
	0x001f 00031 (x.go:8)	MOVQ	BP, 232(SP)
	0x0027 00039 (x.go:8)	LEAQ	232(SP), BP
	0x002f 00047 (x.go:8)	FUNCDATA	$0, gclocals·7d2d5fca80364273fb07d5820a76fef4(SB)
fatal: morestack on g0
<hang>

Presumably fails due to the SIGPIPE from head.

Probably a result of the libc darwin changes. Possibly a duplicate of other, known bugs, but filing because it reproduces 100%.

@randall77

[CAFxX]

This likely happens also on golang 1.10.2: #23360 (comment)

[randall77]

I believe this is fixed now. Not sure the cause, but this may have been from a period where some signal code was moved to libc and some was still direct syscalls.

I now get:

go tool compile: signal: broken pipe

which is exactly what I get on linux.