Comment 32 for bug 1914147

(In reply to Julien Cristau [:jcristau] from comment #21)
> Do we know when/why this started? Any idea how many users may have been affected, and why?

I think the code that triggers this deadlock was in bug 1325341 (since the lock is `mRCWNLock`), so it has been there for years. I think it's probably some recent changes that change the thread timings and make this deadlock happen more often.
Unfortunately, I can't tell how many users are affected, since it's all about timing to hit this.