I might experience something described in this thread:
But on qemu-emulated SS-20 with latest 10.1_stable kernel
and 10.1 userland.
I thought it was lib/57628 but it was pulled up to 10 branch before 10.1 was cut?
Note, I use self-compiled 32bit i586 qemu on Slackware
qemu-system-sparc -hda /mnt/zip/home/guest/QEMU/sparc-netbsd-15g-compressed-r1.qcow2 -m 1536 -g 1024x768x24 -smp1 -acceltcg,thread=multi,tb-size=256 -M SS-20
if I set -smp to 2, 3 or 4 compiling bigger C++ things like re2c (needed by ninja, needed by meson, needed by gobject-introspection, needed by gtk2) results in hung build process (make install from /usr/pkgsrc)
I see some messages _lwp_ctl (?) can't allocate memory, but powerdown usually works (on 10.1 kernel it resulted in some kernel panic in ffs, so fsck was forced on new boot).
I hope I'll try to install tests.tgz and see if atf catch anything ...