1680103 - Investigate shutdown crashes caused by IOUtils' shutdown blocker and add an nsIAsyncShutdown blocker if necessary

Status: RESOLVED DUPLICATE of bug 1672431

(Toolkit Graveyard :: OS.File, task)

Description

[Emma Malysz]

Right now, we have a nonzero amount of shutdown crashes caused by IOUtils' shutdown blocker: https://crash-stats.mozilla.org/signature/?signature=AsyncShutdownTimeout%20%7C%20profile-before-change%20%7C%20IOUtils%20Blocker&date=%3E%3D2020-11-13T23%3A03%3A00.000Z&date=%3C2020-11-20T23%3A03%3A00.000Z&_columns=date&_columns=product&_columns=version&_columns=build_id&_columns=platform&_columns=reason&_columns=address&_columns=install_time&_columns=startup_crash&_sort=-date&page=1

Barret noted that OS.File avoids causing Shutdown crashes by overriding the shutdown time limit (see https://searchfox.org/mozilla-central/rev/2efcda6dc74c63863fd8f04a6d9d7ac6b09c7eca/toolkit/components/osfile/modules/osfile_async_front.jsm#632).

While we don't want to replicate that behavior, we still need to figue out what is the best path forward. We should investigate a few things here:

1. Why was OS.File configured this way?
2. What files do we get blocked on writing?

mconley had suggested a potential solution could be introducing an nsIAsyncShutdown blocker from IOUtils