This workaround solved the problem in my computer (Ubuntu 17.10 x64): https://bugs.launchpad.net/ubuntu/+source/gnome-software/+bug/1723362/comments/11
$ sudo apt-add-repository ppa:ubuntu-desktop/gnome-software
$ sudo apt update
$ sudo apt upgrade
The problem is caused by snapd-glib, that logs hundreds / thousands of lines per minute in the /var/log/syslog like these:
Jan 29 11:12:28 hostXXX gnome-software[1723]: Ignoring unexpected response
Jan 29 11:12:28 hostXXX gnome-software[1723]: g_byte_array_remove_range: assertion 'index_ + length <= array->len' failed
My /var/log/syslog got 9.5 Gb of size before update the module and purge the content.