Вроде и texlive-full (2017.20170818-1) установлен, matplotlib версии 2.0.0+dfsg1-2+b1 ругается при рисовании:
import matplotlib
matplotlib.rcParams.update({'font.size': 8})
import matplotlib.pyplot as plt
from matplotlib import rc;
rc("text" ,usetex=True)
rc('text.latex',unicode=True)
rc("text.latex",preamble=r"\usepackage{amsmath}\usepackage{amssymb}")
rc('text.latex',preamble=r'\usepackage[utf8]{inputenc}')
rc('text.latex',preamble=r'\usepackage[russian]{babel}')
...
fig = plt.figure()
ax1 = fig.add_subplot(1,1,1,xlabel=r"$\phi,\,\textrm{kV}$",ylabel=r"$q\left(\phi\right),\,\textrm{charge units}$")
File "/usr/lib/python3/dist-packages/matplotlib/dviread.py", line 394, in _fnt_def
raise error_class("missing font metrics file: %s" % fontname)
FileNotFoundError: missing font metrics file: lass0800