Re: [PATCH 5/9] arm64: correctly check for ktrheads

[Catalin Marinas]

On Wed, Aug 14, 2019 at 11:41:27AM +0100, Mark Rutland wrote:
> Since commit:
> 
>   6eb6c80187c55b7f ("arm64: kernel thread don't need to save fpsimd context.")
> 
> ... we skip saving the fpsimd state for kernel threads in
> arch_dup_task_struct(). We determine whether current is a kthread by
> looking at current->mm.
> 
> In general, a non-NULL current->mm doesn't imply that current is a
> kthread, as kthreads can install an mm via use_mm(), and so it's
> preferable to use is_kthread() to determine whether a thread is a
> kthread.
> 
> For consistency, let's use is_kthread() here.
> 
> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>

Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>