After updating my docker environment, I noticed every loading tasks are hanging when trying to add an origin to the storage.
This is also the reason why the docker tests are failing since a couple of days: https://jenkins.softwareheritage.org/view/all/job/swh-docker-dev/
I managed to track the instruction in swh-storage that makes any loading task hanging, this is related to writing to the journal.
By checking the date the issue first appeared in the docker tests, this seems related to the latest released version of swh-journal (0.0.16).
It looks like the issue also appears in production as no "Save code now" requests succeed since the last four days: https://archive.softwareheritage.org/save/#requests