Forgot the fixes line.

* Liam Howlett <liam.howlett@oracle.com> [210407 16:00]:
> When the superuser flushes the entire cache, the mmap_read_lock() is not
> taken, but mmap_read_unlock() is called.  Add the missing
> mmap_read_lock() call.
> 
> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
> ---
>  arch/m68k/kernel/sys_m68k.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
> index 1c235d8f53f3..f55bdcb8e4f1 100644
> --- a/arch/m68k/kernel/sys_m68k.c
> +++ b/arch/m68k/kernel/sys_m68k.c
> @@ -388,6 +388,8 @@ sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
>  		ret = -EPERM;
>  		if (!capable(CAP_SYS_ADMIN))
>  			goto out;
> +
> +		mmap_read_lock(current->mm);
>  	} else {
>  		struct vm_area_struct *vma;
>  
> -- 
> 2.30.0