SIGSEGV crash on SMP Xeon E5, can't build from ports

[Romain Tartière]

On Tue, Jan 24, 2017 at 04:50:58AM +0000, Philipp Michel wrote:
> I think it is related to this bug:
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=211367
> 
> There are reports of several people still having this issue, seemingly all
> on multiprocessor machines.
> 
> Any idea what this could be? I'm at my wits end, all I can think of now is
> to run mono in a bhyve VM to get around this, which makes me a bit sad...

Looking at the backtrace from #211367, the segfault comes from
mono_gchandle_free().  The default Garbage Collector (GC) beeing sgen,
trying to switch to boehm may confirm that this is related to a race
condition in the garbage collection?

mcs has a `--gc=[sgen,boehm]` option to test this quickly, but it should
be possible to tell `./configure` to disable sgen support.

Sorry to not be able to provide more than this: with 4 cores, I can't
remember being hit by this problem.

Romain

-- 
Romain Tartière <romain at FreeBSD.org>  http://people.FreeBSD.org/~romain/
pgp: 8234 9A78 E7C0 B807 0B59  80FF BA4D 1D95 5112 336F (ID: 0x5112336F)
(plain text =non-HTML= PGP/GPG encrypted/signed e-mail much appreciated)
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 659 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-mono/attachments/20170124/fbb5dfc0/attachment.sig>