On Tue, Apr 20, 2021 at 11:20:19PM +0200, Arnd Bergmann wrote:
> In that case, there should be no problem for you.
>
> The main issue is with system calls and ioctls that contain a misaligned
> struct member like
>
> struct s {
> u32 a;
> u64 b;
> };
>
> Passing this structure by reference from a 32-bit user space application
> to a 64-bit kernel with different alignment constraints means that the
> kernel has to convert the structure layout. See
> compat_ioctl_preallocate() in fs/ioctl.c for one such example.
We've also had this problem with some on-disk structures in the past,
but hopefully people desining those have learnt the lesson by now.
