Thank you so much all for your replies!! As I saw someone posted 'SAS just informed me in writing that small, fragile stringed instruments such as violins, fiddles, mandolins, etc are now banned as carry-on items on their planes. Their exact words were
"A violin (with normal measurements)will not fit within the maximum measurments thus not possible to bring it on board."' 7 years ago, I was really worried. But it seems no one here has ever got such troubles...I'll bring my violin and see how it goes

Thanks again!
ana