Information about hat creates upset (7)
I believe the answer is:
capsize
'upset' is the definition.
(I've seen this before)
'information about hat' is the wordplay.
'information' becomes 'size' (I can't justify this - if you can you should believe this answer much more).
'about' says to put letters next to each other.
'hat' becomes 'cap' (cap is a type of hat).
'size' after 'cap' is 'CAPSIZE'.
'creates' acts as a link.
Can you help me to learn more?
(Other definitions for capsize that I've seen before include "Of boat, turn turtle" , "Overturn (a boat)" , "Upset" , "Turn so that keel faces upwards" .)