[fedora-virt] Another weird KVM glitch

[Tom Horsley]

I've been looking at a few days worth of testbed results,
and rarely (but more than once) a fantastically weird failure
happens:

Some random process (bash, gcc, etc) will die with a
Trace/Breakpoint trap reported as the reason for the abort.

I am running tests of debugging on most of the virtual
machines, but I'm not debugging these apps, I'm debugging
other stuff on other virtual machines.

It is almost like the emulation code is looking at stale
register values when reporting a breakpoint or address
trap and directing it to the wrong process. So far, I've
never seen this on my Xeon based host, only on my Opteron
based host.

There are 8 CPUs on this thing. I wonder if there is
a missing lock somewhere in some infrequently executed
code path.