what does middle guard protection failed %d mean?

Question

When I build my app to my actual iPhone the debug area shows this:

[Allocator] Middle guard protection failed %d
[Allocator] Allocator invalid, falling back to malloc

It shows the 2nd line a total of 30 times. I have no idea what it means or how to fix it. It does not show this when I build to the simulator.

I am having issues with getting state preservation to work using storyboards and restoration ID's and I have a feeling this has something to do with a memory issue so it's dumping my memory and therefore I get no app restoration. Basically, when I go back to my app it shows me the last screen I was on for a second and then goes back to the root page.

Anyway, I'd like to fix this malloc stuff so I can at least rule it out the culprit, plus I don't want to have an issue with memory in general...

I've been googling this for a couple of weeks now too and can't find anything!

Answer 1

Looks like it's an issue with the Crashlytics framework. I have the same issue, and commenting this API call:

[Crashlytics startWithAPIKey:API_KEY];

removes that warning.

Answer 2

It does indeed seem to be an issue at Crashlytics. I know from other threads that they raised the "Allocator invalid..." issue in relation to another Middle error (not Middle guard protection failed %d), which later got marked as fixed.

I fixed this by deleting all the crashlytics stuff and using the new fabric/crashlytics framework. Problem solved.

(Interestingly, I had it only on an iPad, my iPhone 5C made no complaints at all.)