KASAN caught another use-after-free on my development machine today, see
the attached dmesg excerpt. There haven't been any related changes in
amd-staging-drm-next since yesterday, so maybe userspace is just
tickling the kernel differently (e.g. piglit runs some more tests in
parallel now). It's not reproducible every time, but it just happened a
second time (with an amd-staging-drm-next commit from about a week ago).