On Fri, Jun 21, 2019 at 01:56:16PM +1000, Stephen Rothwell wrote: > Hi Jens, > > After merging the block tree, today's linux-next build (x86_64 > allmodconfig) failed like this: > > ERROR: "css_next_descendant_pre" [block/bfq.ko] undefined! I think the culprit is "bfq-iosched: move bfq_stat_recursive_sum into the only caller" as that starts using css_next_descendant_pre in bfq. I'll send a patch to export it.