From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 18 Nov 2014 15:39:32 +0000
Subject: Re: [patch] exit: silence a bogus static checker warning
Message-Id: <20141118153932.GA3790@redhat.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20141118074422.GA17829@mwanda>
In-Reply-To: <20141118074422.GA17829@mwanda>
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To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Michal Hocko <mhocko@suse.cz>, Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Rik van Riel <riel@redhat.com>, Ionut Alexa <ionut.m.alexa@gmail.com>, Peter Hurley <peter@hurleysoftware.com>, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org

On 11/18, Dan Carpenter wrote:
>
> Smatch complains about this:
>
> 	kernel/exit.c:543 forget_original_parent()
> 	warn: add some parenthesis here?
>
> I don't normally advocate changing the code to make the static checker
> happy but these are normally precedence bugs so I think it's ok to put
> parenthesis so it's clear the code is deliberate.

I still think that "if (!A = B)" doesn't look as a potential precedence
bug, but I won't argue.

Andrew, this fixes   exit-reparent-cleanup-the-changing-of-parent.patch
in -mm tree.

> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/kernel/exit.c b/kernel/exit.c
> index 6192422..1192d12 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -540,7 +540,7 @@ static void forget_original_parent(struct task_struct *father)
>  	list_for_each_entry(p, &father->children, sibling) {
>  		for_each_thread(p, t) {
>  			t->real_parent = reaper;
> -			BUG_ON(!t->ptrace != (t->parent = father));
> +			BUG_ON((!t->ptrace) != (t->parent = father));
>  			if (likely(!t->ptrace))
>  				t->parent = t->real_parent;
>  			if (t->pdeath_signal)