Host operating system: output of uname -a

FreeBSD hostname.example.org 12.1-RELEASE-p3 FreeBSD 12.1-RELEASE-p3 GENERIC amd64

node_exporter version: output of node_exporter --version

  node_exporter, version 1.0.0 (branch: release-1.0, revision: 0)
  build user:       root
  build date:
  go version:       go1.14.3

node_exporter command line flags

/usr/local/bin/node_exporter \
  --web.listen-address=:9100 \
  --collector.textfile.directory=/var/tmp/node_exporter \
  --collector.ntp \
  --collector.devstat

Are you running node_exporter in Docker?

No

What did you do that produced an error?

Scraped the filesystem metrics

What did you expect to see?

Regular old filesystem metrics

What did you see instead?

Filesystem metrics whose label values contained null bytes

A PR for this issue will be raised shortly.