iOS5 crashes during runMode:beforeDate:

I have a problem with compatibility of my application with an iOS5 b7 and GM versions.

The issue occurs in the next lines of code:

do {
    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
} while (!done);

App crashes with signal EXC_BAD_ACCESS after some iterations.

The number of passed iterations is random (from 2 till 7).

Also everything works quite well on iOS4 and iOS3.

The same issue occurs in Apple's sample: XMLPerformance Sample.

What do you think about this?

October 12th thousands of users of my app will upgrade to iOS5 and I don't want my app to be with such a strange error in the AppStore.