[Issue 17037] std.concurrency has random segfaults

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17037

safety0ff.bugz <safety0ff.bugz at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Hardware|x86_64                      |All
                 OS|Linux                       |All

--- Comment #3 from safety0ff.bugz <safety0ff.bugz at gmail.com> ---
Seems to be a race involving the global scheduler:
__gshared Scheduler scheduler;
    @property ref ThreadInfo thisInfo() nothrow
    {
1:        if ( scheduler is null )
2:            return ThreadInfo.thisInfo;
3:        return scheduler.thisInfo;
    }

If a thread sets scheduler to null after another has evaluated line 1 to false
but hasn't run line 3,
then the other thread tries to run scheduler.thisInfo with a null scheduler.

I'm not sure what the design is for the global scheduler is with regard to
concurrent access.

I.e. I'm wondering if all the `scheduler is null` checks be changed to:

auto lscheduler = atomicLoad(scheduler);
if (lscheduler is null)
    return ...;
lscheduler. ... //

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