Recently I attended couple of interviews. Out of all kernel questions which were asked, thr is one specific question which I couldnt find convincing answer of. How will you use different synchronization techniques while sharing data between user space process and interrupt context function? My convincing answer was: In interrupt context code: 1. do *spin_lock_irqsave* 2. access data buffer which is shared between user space app and kernel 3. do *spin_lock_irqrestore* Then this was not convincing answer. Do I have to do irqsave and irqrestore in all the instances of data access? Regards, Yogi