Comment 7 for bug 1556419

Tested the final 4.5 kernel; and the error is not shown:

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kernel: ip_tables: (C) 2000-2006 Netfilter Core Team
kernel: nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
ureadahead[281]: ureadahead: Error while tracing: No such file or directory
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(note: the "ureadahead" error seeems related to the recent "ltrace" changes, as the package has not been rebuilt. But ubuntu-minimal should not pull that oldish package as systemd is now used)

(note2: the post #4 above explain how to compile the kernel to avoid the reported error; looks like the ubuntu kernel does not use these settings for compilation)