Wrong goroutine on newstack

[Gustavo Niemeyer]

The following panic was observed by two independent developers [1],
both on 32bit Linux VMS, while 64bit VMs seem to work fine. This was
on Go 1.2.1, and I asked whether it still happens on tip:

runtime: newstack called from g=0x93be5140
m=0x93bf3000 m->curg=0x0 m->g0=0x93be51e0 m->gsignal=0x93be5140
fatal error: runtime: wrong goroutine in newstack

From the full traceback [2], this is happening during a call where Go
calls C calls Go, right at the entrance back into Go.

Would anyone have a clue, before I try to setup an environment to dig
further into it?


[1] https://github.com/go-qml/qml/issues/43
[2] https://gist.github.com/tummychow/9046195


gustavo @ http://niemeyer.net

[Russ Cox]

this sounds like qml overwriting our signal handler setup. in particular it seems to have removed our sigaltstack setting or cleared SA_ONSTACK in the handler.

[Gustavo Niemeyer]

Ok, so similar to #7227 in essence. I thought this was happening on
Mac OS only, and due to a system library. I'll dig deeper to see what
might be going on there. Thanks.

--

gustavo @ http://niemeyer.net