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Date: Mon, 26 Mar 2018 12:27:50 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: kmemleak: wait for scan completion before disabling
 free
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	<20180326154421.obk7ikx3h5ko62o5@armageddon.cambridge.arm.com>
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To: Catalin Marinas <catalin.marinas@arm.com>, Vinayak Menon <vinmenon@codeaurora.org>, linux-mm@kvack.org

On Mon, 26 Mar 2018 12:26:11 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:

> > 
> > It looks fine to me. Maybe Andrew can pick it up.
> > 
> > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> 
> Well, the comment says:
> 
> /*
>  * Stop the automatic memory scanning thread. This function must be called
>  * with the scan_mutex held.
>  */
> static void stop_scan_thread(void)
> 
> 
> So shouldn't we do it this way?

If "yes" then could someone please runtime test this?

> --- a/mm/kmemleak.c~mm-kmemleak-wait-for-scan-completion-before-disabling-free-fix
> +++ a/mm/kmemleak.c
> @@ -1919,9 +1919,9 @@ static void __kmemleak_do_cleanup(void)
>   */
>  static void kmemleak_do_cleanup(struct work_struct *work)
>  {
> +	mutex_lock(&scan_mutex);
>  	stop_scan_thread();
>  
> -	mutex_lock(&scan_mutex);
>  	/*
>  	 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
>  	 * longer track object freeing. Ordering of the scan thread stopping and
> _
>