We've made a lot of progress with MemShrink in just a few months. There's plenty more work to do, but at this point, the vast majority of bugs which take the form of "OMG Firefox is using 8 zettabytes of RAM" are not due to problems in Firefox. Instead, most major memory bugs are due to problems in Firefox add-ons.

We in MemShrink have generally argued that bugs caused by add-ons aren't something we can fix, so fixing them can't be a priority. We've reached out to the developers of the leaky add-ons we've been made aware of, and we've discussed strategies to automatically fix certain classes of add-on leaks. But the first approach doesn't scale, and the second approach is Very Hard and unlikely to happen.

No add-on is immune from the risk of leaking. Even the venerable Adblock Plus, the most popular add-on on AMO and by all measures a well-written add-on, suffers from a compartment leak.

Given that add-ons are so frequently fingered as the causes of leaks, and given that so many add-ons leak, my thesis is that we should stop using the fact that we don't control add-ons' code as an excuse not to try to fix this situation.

The fact is, if we take credit for our vibrant add-on community, we must take responsibility for the problems those add-ons cause. This shouldn't be controversial; we already check to ensure that add-ons aren't outright malicious before posting them to AMO, acknowledging that the buck stops at Mozilla when there's a misbehaving add-on. Even if it's not our bug, it's in our software, and people will blame us, not their add-ons.

So what can we do to fix this? I suggest a three-pronged approach, consisting of the carrot, the stick, and the wrench:

It's time for us to stop saying there's nothing we can do to fix problems caused by add-ons. We can give developers the tools they need to solve leaks, we can give them the incentives to fix those leaks, and we can empower users so they know what they're getting themselves into when they install an add-on.

People love their add-ons, and we need to ensure that running Firefox plus a few popular add-ons is as awesome an experience as running Firefox with no add-ons.