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Subject: RE: [PATCH] mailbox: imx-mailbox: fix scu msg header size check
Thread-Topic: [PATCH] mailbox: imx-mailbox: fix scu msg header size check
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Date:   Tue, 14 Apr 2020 08:40:19 +0000
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> Subject: Re: [PATCH] mailbox: imx-mailbox: fix scu msg header size check
>=20
> On Tue, Apr 14, 2020 at 04:10:26PM +0800, peng.fan@nxp.com wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > The i.MX8 SCU message header size is the number of "u32" elements, not
> > "u8", so fix the check.
> >
> > Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
> > Addresses-Coverity-ID: 1461658 ("Memory - corruptions")
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >
> > V2:
> >  I not include the fixes tag, since this patch still in next tree.
> >
> >  drivers/mailbox/imx-mailbox.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/mailbox/imx-mailbox.c
> > b/drivers/mailbox/imx-mailbox.c index 7906624a731c..c2398cb63ea0
> > 100644
> > --- a/drivers/mailbox/imx-mailbox.c
> > +++ b/drivers/mailbox/imx-mailbox.c
> > @@ -154,12 +154,12 @@ static int imx_mu_scu_tx(struct imx_mu_priv
> > *priv,
> >
> >  	switch (cp->type) {
> >  	case IMX_MU_TYPE_TX:
> > -		if (msg->hdr.size > sizeof(*msg)) {
> > +		if (msg->hdr.size > (sizeof(*msg) / 4)) {
>=20
> No need for the parenthesis. Maybe a comment would be helpful here,
> something like:
>=20
> 	/*
> 	 * msg->hdr.size specifies the number of u32 words while sizeof
> 	 * yields bytes.
> 	 */

V2 will have the update.

>=20
> >  			/*
> >  			 * The real message size can be different to
> >  			 * struct imx_sc_rpc_msg_max size
> >  			 */
> > -			dev_err(priv->dev, "Exceed max msg size (%zu) on TX,
> got: %i\n", sizeof(*msg), msg->hdr.size);
> > +			dev_err(priv->dev, "Exceed max msg size (%zu) on TX,
> got: %i\n",
> > +sizeof(*msg) / 4, msg->hdr.size);
>=20
> The unit here is also "number of u32 words", maybe bytes is more natural?

ok. Will change to msg->hdr.size << 2 keeping sizeof(*msg).

> And I suggesting specifying the unit in the error message.

Is this ok to you?
dev_err(priv->dev, "Exceed max msg size (%zu) on TX, got: %i,=20
msg->hdr.size: %i\n", sizeof(*msg), msg->hdr.size << 2, msg->hdr.size);

Thanks,
Peng.

>=20
> Best regards
> Uwe
>=20
> --
> Pengutronix e.K.                           | Uwe Kleine-K=F6nig
> |
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