iOS7 - App causes device (not app) to crash

Question

Our company has an app which is basically an eBook reader.

We use the RMSDK to perform book downloads & read.

Now, something very strange is happening in iOS7 devices (not in the simulator):

1. I download a book using the fulfillment method in the RMSDK
2. I wait for the book to finish downloading. The book is saved in the NSCachesDirectory (for App Store guidelines reasons) - so far, everything works fine
3. I hit the home button, the app moves to the background
4. I hit the app button to bring the app back, that's when the problem happens:

The app gets completely stuck. Hitting the home button does nothing, hitting the power button shuts down the screen, but then hitting the power button again does nothing. The device itself has effectively crashed.

After a few minutes, the Apple logo appears on the device and the device comes back to life after a reboot.

I have no idea what in my code could be causing the device to act this way. Shouldn't the iOS7 sandbox prevent me from being able to crash the whole device?

Any ideas on why this could be happening and what I can do to prevent it would be greatly appreciated.

EDIT: I placed a breakpoint on the -(void)applicationDidBecomeAcvive: method in the AppDelegate, and it's not being called when clicking on the app icon in the last phase before the crash.

EDIT: The RMSDK is using libcurl to download the books. Could this be a cause for this behavior?

EDIT: The problem is happening if I click on ANY app after I click on the home button, not just on the same app. So for example, I click on the home button, then I try to open Fruit Ninja , and the device crashes.

Answer 1

We managed to solve this issue by disabling functions in RMSDK, which call mkfifo() . I'm not sure how much I can say here due to NDA but they're all located in one file and can be cleanly converted to no-ops with a nice preprocessor #if defined()

Answer 2

Its an OS level bug. iOS 7 is still unstable in areas, for example my Apps report crashes in places that are part of iOS 7 itself and couldn't be caused by my app.