linux-kernel - Re: [lvc-project] [PATCH] remoteproc: imx_rproc: Adjust phandle parsing issue while remapping optional addresses in imx_rproc_addr

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Date: Tue, 11 Jun 2024 10:45:27 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Fedor Pchelkin <pchelkin@...ras.ru>
Cc: Aleksandr Mishin <amishin@...rgos.ru>, imx@...ts.linux.dev,
	lvc-project@...uxtesting.org, Shawn Guo <shawnguo@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>,
	linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Oleksij Rempel <o.rempel@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	linux-arm-kernel@...ts.infradead.org, Peng Fan <peng.fan@....com>
Subject: Re: [lvc-project] [PATCH] remoteproc: imx_rproc: Adjust phandle
 parsing issue while remapping optional addresses in imx_rproc_addr_init()

On Mon, Jun 10, 2024 at 08:36:19PM +0300, Fedor Pchelkin wrote:
> On Mon, 10. Jun 10:47, Mathieu Poirier wrote:
> > On Thu, Jun 06, 2024 at 10:52:04AM +0300, Aleksandr Mishin wrote:
> > > In imx_rproc_addr_init() "nph = of_count_phandle_with_args()" just counts
> > > number of phandles. But phandles may be empty. So of_parse_phandle() in
> > > the parsing loop (0 < a < nph) may return NULL which is later dereferenced.
> > > Adjust this issue by adding NULL-return check.
> > > 
> > > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > > 
> > > Fixes: a0ff4aa6f010 ("remoteproc: imx_rproc: add a NXP/Freescale imx_rproc driver")
> > > Signed-off-by: Aleksandr Mishin <amishin@...rgos.ru>
> > > ---
> > >  drivers/remoteproc/imx_rproc.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> > > index 5a3fb902acc9..39eacd90af14 100644
> > > --- a/drivers/remoteproc/imx_rproc.c
> > > +++ b/drivers/remoteproc/imx_rproc.c
> > > @@ -726,6 +726,8 @@ static int imx_rproc_addr_init(struct imx_rproc *priv,
> > >  		struct resource res;
> > >  
> > >  		node = of_parse_phandle(np, "memory-region", a);
> > > +		if (!node)
> > 
> > You're missing an "of_node_put()" before continuing.
> > 
> 
> The node is NULL in this case so of_node_put() is not needed..?

Oh yeah, doing a of_node_put() with a NULL value is are really good idea...

I will pickup this patch.

> 
> Btw, there is a "rsc-table" node->name check in the the end of the loop
> body. It was added recently with commit 5e4c1243071d ("remoteproc:
> imx_rproc: support remote cores booted before Linux Kernel"). Seems to me
> it forgot that of_node_put() is called way before that.
> 

I agree.

> Also commit 61afafe8b938 ("remoteproc: imx_rproc: Fix refcount leak in
> imx_rproc_addr_init") was dealing with the last of_node_put() call here
> but it's still not in the right place I'd say.
>

You mean becaue of node->name being used after the last of_node_put() or is
there something else?

Aleksandr - Can you send another patch for the above?

Thanks,
Mathieu

> > > +			continue;
> > >  		/* Not map vdevbuffer, vdevring region */
> > >  		if (!strncmp(node->name, "vdev", strlen("vdev"))) {
> > >  			of_node_put(node);
> > > -- 
> > > 2.30.2
> > > 
> > >