On Tue, Apr 25, 2023 at 02:34:15PM +0200, Christian Brauner wrote: > struct fd_file { > struct file *file; > int fd; > int __user *fd_user; Why is it an int? Because your case has it that way? We have a bunch of places where we have an ioctl with a field in some structure filled that way; any primitive that combines put_user() with descriptor handling is going to cause trouble as soon as somebody deals with a structure where such member is unsigned long. Gets especially funny on 64bit big-endian... And that objection is orthogonal to that 3-member structure - even if you pass int __user * as an explicit argument into your helper, the same trouble will be there. Al, still going through that zoo...