Attempted to add a genre (classical, as it happens) to all (8) tracks of an album that lacked genre tags on any of the tracks. Selected all 8 tracks and the album. Lockup appears similar to
PICARD-1926. strace shows a fast loop of futex operations.
This is the git repo hash be7b578c7519d8c34ef3eb3762fc09a8fa00f198
$ picard --version
MusicBrainz Picard 2.6.0.dev1