Now looking closer at the patch, I noticed that the parameter passed to md_io_acct() is different from the original code; op_stat_group(bio_op(bio)) was the original version while bio_op(bio) is the new one. Now I'm building yet another kernel with the corrected patch in OBS home:tiwai:bsc1173860-2 repo. It'll appear later at http://download.opensuse.org/repositories/home:tiwai:bsc1173860-2/standard Could you give it a try this one, too?