contrib/torctl script sends SIGHUP without running tor --verify-config first
The torctl script in Tor's contrib/ directory supports a reload command which sends SIGHUP to the running Tor process, but it doesn't check the new configuration for validity with tor --verify-config
first, and it doesn't check to see whether Tor is still running after it sends the SIGHUP. This can lead to Tor exiting without the user noticing that there is a problem.
Slackware's Tor package installs and uses this script; other distributions may package it for users, too.