re: port-sparc/56788 Rump kernel panic: kernel diagnostic assertion "old == LOCK_LOCKED" failed

[matthew green <mrg%eterna.com.au@localhost>]

nice work Tom.

>  It's striking though that SPARC is not in this list.  Perhaps
>  it has some related failure mechanism?  I see that
>  src/common/lib/libc/arch/sparc/atomic/atomic_cas.S
>  makes use of a "locktab array" that looks like it'd have the
>  same problem of being process-local, but I am not sure if that
>  code is used in a rump kernel, or whether it applies to the
>  SPARC variant being complained of here.

yeah - sparc uses a similar mechanism last i looked at this,
and tried to figured out why rump_server and more would not
exit on sparc, and it always came down to mutexes not working
like you're described here, but i didn't think about shared
process spaces not being shared now.

we knew this was a problem with some code bases (eg, related
to shared futexes), but i did not know this was used by our
own code/tests.


.mrg.