Comment 12 for bug 1215513

dac922, thanks a lot for your analysis. I've uploaded a test kernel here:

 http://people.canonical.com/~henrix/lp1215513/

(there are 2 directories, one for 32bits and another for 64bits)

Could the original bug reporter please also test it and report back?

This is a Raring kernel reverting commit referred in comment #11 (upstream commit 57ab048 "zram: use zram->lock to protect zram_free_page() in swap free notify path"). This commit actually introduces a regression that is fixed upstream but its backport to Raring seems to require a few additional commits.

Thanks.