Re: Mach panic: thread has unexpected state

[Sergio López]

2011/9/22  <olafBuddenhagen@gmx.net>:
> Hi,
>
> While shutting down a subhurd today, I encounted a Mach panic; and I
> already encountered a rather similar one once a couple of months ago.
> (Might also have been while shutting down subhurd, but I can't say for
> sure anymore.) I'm attaching both traces -- perhaps someone gets an
> idea.
>
> Note that the thread state is 14 in one and 114 in the other -- most
> likely I simply mistyped it in one of them, as I can only write down the
> panic message by hand...

Actually, both numbers can be valid, as the value for TH_SWAPPED flag
is 0x100. It seems like a thread has the flags TH_RUN and TH_HALTED,
but not TH_SUSP, and thread_invoke doesn't expect this.

The only path I found that could lead to this situation, is
thread_release or thread_resume being called for a thread with
AST_HALT flag before this one is scheduled, as those functions clear
TH_HALTED and TH_SUSP flags, without checking for any AST condition.