linux-kernel - Re: [PATCH] of: overlay: fix memory leak of ovcs on error exit path

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Date:   Thu, 30 Nov 2017 15:50:02 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Frank Rowand <frowand.list@...il.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Colin King <colin.king@...onical.com>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] of: overlay: fix memory leak of ovcs on error exit path

On Thu, Nov 30, 2017 at 07:14:45AM -0500, Frank Rowand wrote:
> On 11/29/17 14:17, Colin King wrote:
> > From: Colin Ian King <colin.king@...onical.com>
> > 
> > Currently if the call to of_resolve_phandles fails then then ovcs
> > is not kfree'd on the error exit path.  Rather than try and make
> > the clean up exit path more convoluted, fix this by just kfree'ing
> > ovcs at the point of error detection and exit via the same exit
> > path.
> > 
> > Detected by CoverityScan, CID#1462296 ("Resource Leak")
> > 
> > Fixes: f948d6d8b792 ("of: overlay: avoid race condition between applying multiple overlays")

The Fixes tag is wrong.  It should be:

Fixes: bd80e2555c5c ("of: overlay: Fix cleanup order in of_overlay_apply()")

> > Signed-off-by: Colin Ian King <colin.king@...onical.com>
> > ---
> >  drivers/of/overlay.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> > index 53bc9e3f0b98..6c8efe7d8cbb 100644
> > --- a/drivers/of/overlay.c
> > +++ b/drivers/of/overlay.c
> > @@ -708,8 +708,10 @@ int of_overlay_apply(struct device_node *tree, int *ovcs_id)
> >  	of_overlay_mutex_lock();
> >  
> >  	ret = of_resolve_phandles(tree);
> > -	if (ret)
> > +	if (ret) {
> > +		kfree(ovcs);
> >  		goto err_overlay_unlock;
> > +	}
> >  
> >  	mutex_lock(&of_mutex);
> >  
> > 
> 
> False coverity warning.  ovcs is freed in free_overlay_changeset().

You're looking at an older version of the code and Colin is looking at
linux-next.

regards,
dan carpenter