After more research, this turns out to be a bizarre interaction of various things. The culprit is the intersection of this version of compiz and running older kernel versions. As soon as we updated to linux-image-3.13.0-49-generic, the problem went away. So I think it's still the case that something in the latest compiz update, at least on that one specific radeon card, is tickling a bug that was present at least as recently as 3.13.0-44, but went away some time between then and the current version. (I do see some radeon-specific notes in the changelog for the package, for the -45, -46, and -47 releases).
(For unrelated reasons, a site-specific script to prune old kernel versions had the side effect, in Trusty, of removing linux-image- generic, due to changed dependencies between trusty and precise. As a result, machines didn't take kernel updates in a timely manner, which is why this bug got noticed, and the failure mode did coincide with the machines taking the latest compiz.) So feel free to close this, unless there's any further info you want. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1449089 Title: Regression: compiz 1:0.9.11.3+14.04.20150313-0ubuntu1 segfaults on Radeon HD 7470/8470 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1449089/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs