From: Dan Carpenter > Sent: 01 February 2023 13:23 > > On Wed, Feb 01, 2023 at 12:34:50PM +0000, David Laight wrote: > > In reality having a uapi structure with embedded padding should > > be banned. > > But that would need a compiler attribute to enforce it. > > It would be simple enough to grep the names of all the UAPI struct and > use pahole to make a list of the existing structs which have holes. > Then re-run the script every week and complain when new holey struct > types are added. > > You could do a similar thing with Smatch looking at copy_to/from_user() > struct types. Would it be possible to add aa attribute and check to sparse? Might persuade people to use it instead of 'packed' for structures that map defined byte layouts and so mustn't be holey - but are never actually misaligned in memory. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
