SUP IOS (LBO)writelock inside an outermost read lock

Hi group,

currently i am implementing SUP IOS application. I am using background synchronization in my application.i am using following code  for synchronization  in SUP IOS code.

            dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND,0UL);

            dispatch_async(concurrentQueue, ^{

                dispatch_async(dispatch_get_main_queue(), ^{

[InspectiInspectiDBsynchronize:@"default"];

                });

            });

.It is performing background synchronization very well. But while i am performing CRUD operations like Create ,update..etc,it is showing  following

error and application gets strucked.

writelock inside an outermost read lock  .

.Can any one guide me.