Re: [PATCH v3] x86/suspend: fix false positive KASAN warning on suspend/resume

Andrey Ryabinin
2016-12-02T16:20:57Z

On 12/02/2016 05:42 PM, Josh Poimboeuf wrote:

> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
> index 0e9505f..e9d8ba0 100644
> --- a/mm/kasan/kasan.c
> +++ b/mm/kasan/kasan.c
> @@ -80,7 +80,14 @@ void kasan_unpoison_task_stack(struct task_struct *task)
> /* Unpoison the stack for the current task beyond a watermark sp value. */
> asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
> {
> - __kasan_unpoison_stack(current, watermark);
> + /*
> + * Calculate the task stack base address. Avoid using 'current'
> + * because this function is called by early resume code which hasn't
> + * yet set up the percpu register (%gs).
> + */
> + void *base = (void *)((unsigned long)watermark & CURRENT_MASK);

CURRENT_MASK is defined only on x86...

> +
> + kasan_unpoison_shadow(base, watermark - base);
> }
>
> /*
>