linux-kernel - Re: [PATCH/RFC] mm, oom: Fix uninitialized ret in task_will_free

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Message-ID: <20160811075451.GA6908@dhcp22.suse.cz>
Date:	Thu, 11 Aug 2016 09:54:51 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Oleg Nesterov <oleg@...hat.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH/RFC] mm, oom: Fix uninitialized ret in
 task_will_free_mem()

On Wed 03-08-16 22:19:59, Geert Uytterhoeven wrote:
>     mm/oom_kill.c: In function ‘task_will_free_mem’:
>     mm/oom_kill.c:767: warning: ‘ret’ may be used uninitialized in this function
> 
> If __task_will_free_mem() is never called inside the for_each_process()
> loop, ret will not be initialized.
> 
> Fixes: 1af8bb43269563e4 ("mm, oom: fortify task_will_free_mem()")
> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>

Acked-by: Michal Hocko <mhocko@...e.com>

Thanks for catching that!

> ---
> Untested. I'm not familiar with the code, hence the default value of
> true was deducted from the logic in the loop (return false as soon as
> __task_will_free_mem() has returned false).
> ---
>  mm/oom_kill.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 7d0a275df822e9e1..d53a9aa00977cbd0 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -764,7 +764,7 @@ bool task_will_free_mem(struct task_struct *task)
>  {
>  	struct mm_struct *mm = task->mm;
>  	struct task_struct *p;
> -	bool ret;
> +	bool ret = true;
>  
>  	/*
>  	 * Skip tasks without mm because it might have passed its exit_mm and
> -- 
> 1.9.1
> 

-- 
Michal Hocko
SUSE Labs