[erlang-questions] dirty scheduler segfault

[Steve Vinoski]

On Fri, Oct 31, 2014 at 4:33 PM, Daniel Goertzen <daniel.goertzen@REDACTED>
wrote:

> I am seeing a segfault that seems to be related to dirty schedulers.  I've
> reduced the fault to the erlang and C nif module below which executes the
> same nif with either the io dirty scheduler, the cpu dirty scheduler, or
> the normal erlang scheduler.
>
>
> When I start the emulator and run either dirty nif, I get a segfault. (
> see https://gist.github.com/goertzenator/6237e0200a5f7bf22976)
>

I found it hard to make sense of what's in that gist due to the formatting,
so I took your code and built it myself. When I ran it, it failed in your
NIF load function, but it failed in a way that didn't make sense because
all your function does is return 0. Then I realized none of your C
functions were declared static, which means they are global, and I
suspected your load() function was clashing with some other function of the
same name. I made all your C functions static, rebuilt, and then ran
everything and it seems like it worked:

> c(dlibusb).
Reading symbols for shared libraries . done
{ok,dlibusb}
2> dlibusb:mytest_cpu().
[ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok]
3> dlibusb:mytest_io().
[ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok]
4> dlibusb:mytest_none().
[ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok]

--steve
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