Whenever this happens, there is another thread waiting to sync buffersNo - as I wrote, I tested only with qemu, without networking. Thus the bh queue was never used. Just booting a complete system with uniprocessor, spinlock debugging enabled immediately showed a bug in line 315: It unlocked rcu_state.lock instead of rsp->lock :-(
(sometimes with several backed up behind him). It was kjournald in this
case. Have you seen this ever with these patches?