Re: [PATCH] time: Zerofy padding in __kernel_timespec on 32-bit

[Arnd Bergmann]

On Thu, Nov 21, 2019 at 1:03 AM Dmitry Safonov <dima@xxxxxxxxxx> wrote:
>
> On compat interfaces, the high order bits of nanoseconds should
> be zeroed out. This is because the application code or the libc
> do not guarantee zeroing of these. If used without zeroing,
> kernel might be at risk of using timespec values incorrectly.
>
> Originally it was handled correctly, but lost during is_compat_syscall()
> cleanup. Revert the condition back to check CONFIG_64BIT.
>
> Reported-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
> Fixes: 98f76206b335 ("compat: Cleanup in_compat_syscall() callers")

Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>