os/signal: tests failing on Plan 9

[0intro]

Since CL 9704, the os/signal tests are failing on Plan 9.

--- FAIL: TestSignal (1.01s)
    signal_plan9_test.go:34: hangup...
    signal_plan9_test.go:22: timeout waiting for hangup
FAIL
FAIL    os/signal   1.195s

http://build.golang.org/log/920e12e956c8f974b0e79fcdd6c0cdb056d4e222

[0intro]

It seems the value of the note got deallocated between push and pop. Why does it happen?

src/runtime/sigqueue_plan9.go

sendNote "hangup"
push 0x10328c90 "hangup"
pop 0x10328c90 ""
signal_recv ""

[gopherbot]

CL https://golang.org/cl/9950 mentions this issue.