[strcat]

> The tradeoff isn't just memory use or performance -- it's also user-facing crashes that weren't present before. That is likely the bigger factor in deciding whether or not to enable the feature.

We're only proposing enabling it for the base OS and user installed apps opting into it. Google has already fixed nearly all the crashes due to testing with HWAsan and MTE. They don't test enough with real world usage yet because they haven't deployed it for all the dogfooding devices. To do that, they need to set up enabling it for the base OS without enabling it for all user installed apps because that's not currently very practical. Google has already done most of the work for enabling it for the base OS, not us. We have to fix some bugs, but they're almost all regressions which don't live past the next quarterly releases since they do find and fix them. Google is 100% capable of enabling MTE for the Pixel stock OS within the base OS without a significant increase to crashes for users. In fact, it will significantly decrease user-facing crashes once it matures. It will result in so many memory corruption bugs being fixed. Testing internally with MTE doesn't do the same thing as deploying it to production in terms of bug fixing and also doesn't provide hardening against the bugs not occurring during regular usage.

[saagarjha]

I don’t understand your argument here. Google has been working on fixing the their own crashes with the data they have right now. Why would they turn it on for everyone else while they do that?

[strcat]

They have already fixed nearly all the crashes in the base OS. The issues we face are almost entirely regressions in new versions. They fix them consistently but they aren't stopping the regressions getting into releases because they don't use MTE in production.

[saagarjha]

Regressions from whom?

[strcat]

Regressions in Android because they aren't doing enough real world testing with MTE or HWASan builds. They're clearly testing them via CI and fixing those issues but in real world usage more issues are uncovered which often slip into releases then get fixed in another release a few months later.