linux-kernel - Re: [PATCH] ocfs2: fix snprintf() checking

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Date:   Tue, 11 May 2021 16:52:29 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Joseph Qi <joseph.qi@...ux.alibaba.com>
Cc:     Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Gang He <ghe@...e.com>, ocfs2-devel@....oracle.com,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] ocfs2: fix snprintf() checking

On Tue, May 11, 2021 at 08:54:53PM +0800, Joseph Qi wrote:
> 
> 
> On 5/11/21 3:16 PM, Dan Carpenter wrote:
> > The snprintf() function returns the number of bytes which would have
> > been printed if the buffer was large enough.  In other words it can
> > return ">= remain" but this code assumes it returns "== remain".
> > 
> > The run time impact of this bug is not very severe.  The next iteration
> > through the loop would trigger a WARN() when we pass a negative limit
> > to snprintf().  We would then return success instead of -E2BIG.
> > 
> > The kernel implementation of snprintf() will never return negatives so
> > there is no need to check and I have deleted that dead code.
> > 
> > Fixes: a860f6eb4c6a ("ocfs2: sysfile interfaces for online file check")
> > Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> 
> Looks good. But the last 2 sections are introduced by:
> 74ae4e104dfc ocfs2: Create stack glue sysfs files.
> 
> With 'Fixes' tag updated,
> Reviewed-by: Joseph Qi <joseph.qi@...ux.alibaba.com>
> 

Thanks!  Will do.

regards,
dan carpenter