I also see it on Ubuntu 16.04 on another system: Linux blackbox 4.4.0-75-generic #96-Ubuntu SMP Thu Apr 20 09:56:33 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux ii linux-image-4.4.0-75-generic 4.4.0-75.96 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
I'll try with 4.8.0 on Ubuntu as well, but am expecting the same behavior. For me this is with a FreeNAS server. Should I file this bug with Ubuntu as well? Does it make sense to file it upstream with the kernel directly?