From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by smtp.lore.kernel.org (Postfix) with ESMTP id C25A1C4321E
	for <linux-kernel@archiver.kernel.org>; Wed, 16 Nov 2022 18:17:01 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S238775AbiKPSQ6 (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Wed, 16 Nov 2022 13:16:58 -0500
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55410 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S238854AbiKPSQp (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 16 Nov 2022 13:16:45 -0500
Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4F4E6314F;
        Wed, 16 Nov 2022 10:16:43 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
        d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version:
        References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:
        Content-Transfer-Encoding:Content-ID:Content-Description;
        bh=3QlE2bOOn3d9ibwxdimqr4/FiU3pKkYhXqcHPHT4Nog=; b=MqnUG3fItIqA4aopRIW4CFI+M4
        PtCt++JZtk2E0rSA5HFsBG+tI3p2640KnmIq1d/97x+eXOFnmQVchRlszcZvqlvQvkneE/Q1RtIHn
        ZmnZJa/nhOkhFllZ6XZXGHm3ecE7oFdK3wvkT0A6g6Ek0vX0y1MWFUIG3rvr2fnkRWdwWJhhyyhJL
        4RZ9FBu3cmyy/gDSw10IrmdtDwt2GnL6IQ0pdVWR21ciu2zyk/1m+12KzbdwY3GRFZfrfl6JsA6Y6
        eU+SMY9P581WLA7Se3c4kUA7Xy/PzAZNM9dRP3z74ZTeYZ+ZTNskyzAEAPhSch0tLef/4O9OH70MK
        gOBngGMQ==;
Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux))
        id 1ovMxn-0004rs-Jg; Wed, 16 Nov 2022 18:16:43 +0000
Date:   Wed, 16 Nov 2022 18:16:43 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Denis Arefev <arefev@swemel.ru>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        trufanov@swemel.ru, vfh@swemel.ru
Subject: Re: [PATCH] namespace: Added pointer check in copy_mnt_ns()
Message-ID: <Y3UpC8AT8gTeupib@casper.infradead.org>
References: <20221116091255.84576-1-arefev@swemel.ru>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20221116091255.84576-1-arefev@swemel.ru>
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Nov 16, 2022 at 12:12:55PM +0300, Denis Arefev wrote:
> Return value of a function 'next_mnt' is dereferenced at
> namespace.c:3377 without checking for null,
>  but it is usually checked for this function
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.

You need to do human analysis, not just send the results from a bot.
What conditions can lead to this function returning NULL?  Do we
already know those conditions can or cannot hold?