From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: [PATCH v3] x86/suspend: fix false positive KASAN warning on
 suspend/resume
Date: Fri, 2 Dec 2016 17:45:18 +0300
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To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>, linux-pm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@amacapital.net>, Scott Bauer <scott.bauer@intel.com>, "x86@kernel.org" <x86@kernel.org>, Alexander Potapenko <glider@google.com>, kasan-dev <kasan-dev@googlegroups.com>



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);
>  }
>  
>  /*
>