emacs23 and emacs24 search display bugs on machines with multiple cpus

[Peter Tripp]

An Ubuntu system with multiple cpus corrupts the display while searching. This is reproducible via ssh as well as on a local terminal. I've seen this under Ubuntu 14.04.2 with emacs23 (23.4+1-4.1ubuntu1) and emacs24 (24.3+1-2ubuntu1).

Here's an askubuntu question with reproduction instructions and a screenshot:
http://askubuntu.com/questions/418546/emacs-screen-drawing-issues-over-ssh

1. emacs ~/.bash_history
2. C-s cd (incremental search for "cd")
3. keep hitting C-s (aka jump to the next search result)

This can be easily reproduced under VirtualBox, create a VirtualBox vm with two vcpus, search in emacs and terrible things happen. Reduce to one vcpu and everything's peachy keen.

Martin Trojer posted a patch to bug-gnu-emacs mailing list which fixed it for me:
https://lists.gnu.org/archive/html/bug-gnu-emacs/2015-03/msg00698.html
https://github.com/martintrojer/emacs/commit/bdff1ff98d02f4307659c052d0b35a40a36f0706

This patch is attached.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Fixes emacs search display bug with multiple cpus" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Peter Tripp (notpeter)]

Here's a link in the GNU.org bug tracker:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=17497