something's wrong

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

For testing rmind's latest tmpfs patch on
NetBSD-6.99.25/amd64/clang/libc++, I ran my usual pbulk-in-a-tmpfs
test and very repeatable got system hangs (not panics). I have since
reverted to a tmpfs-bugfix version that was working stably for me for
a long time and still see this behaviour.

They all have in common that the USB keyboard and mouse stop working.
Sometimes I was sitting in front of the machine and could look at the
widgets I have running (in X) to report network traffic and the
current time. Here I saw the following behaviours:

* Both network and time widget keep working (!)

* (No network activity) time widget jumps between two seconds, e.g.
10:13:53 and 10:53:54, displaying 10:13:53 for ~3 seconds, switching
to 10:13:54 for a very short time and then switching back.

* Complete hang, no activity.

A good way to cause this seems to be building lang/mono2, which is
infamous for its not-quite-correct use of libpthread. For this reason
my best guess is that it's something to do with libpthreads.

I don't understand the behaviour I'm seeing though.

Please note that the machine doesn't panic -- otherwise I'd have seen
reboots instead.

I'm regularly updating, so I think this problem is rather new (last
month or so). I was usually running with clang; using libc++ is new,
no idea if this is related or not (I guess not).

Does anyone have any ideas about this?

Thanks,
 Thomas