一般的问题是这样的

“bool _WebTryThreadLock(bool), 0xxxxxx: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now…”

原因: update ui in background thread.

解决办法: update ui in main thread.

示例:

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dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    // Do time-consuming task in background thread
    // Return back to main thread to update UI
    dispatch_sync(dispatch_get_main_queue(), ^{
        _profile = [[UITextView alloc] init];
        [_profile setFrame:CGRectMake(labelPersonProfileCaption.frame.origin.x, labelPersonProfileCaption.frame.origin.y + labelPersonProfileCaption.frame.size.height, width, height - 30.0)];
        
        _profile.layer.borderColor = [[UIColor lightGrayColor] CGColor];
        _profile.layer.borderWidth = 1.0;
        _profile.layer.cornerRadius = 10.0;
        _profile.delegate = self;
        _profile.text = @"";
        _profile.backgroundColor = [UIColor lightGrayColor];
        _profile.editable = NO;
        _profile.font = [UIFont systemFontOfSize:14.0];
        _profile.backgroundColor = [UIColor whiteColor];
        
        [_contentScroll addSubview:_profile];
    });
});

参考资料：http://blog.csdn.net/chuwachen/article/details/8718253