Re: [PATCH] net: stmmac: add sanity check to device_property_read_u32_array call

[Martin Blumenstingl]

Hi Colin,

On Thu, Jun 20, 2019 at 3:34 AM Martin Blumenstingl
<martin.blumenstingl@xxxxxxxxxxxxxx> wrote:
>
> Hi Colin,
>
> On Wed, Jun 19, 2019 at 8:55 AM Colin Ian King <colin.king@xxxxxxxxxxxxx> wrote:
> >
> > On 19/06/2019 06:13, Martin Blumenstingl wrote:
> > > Hi Colin,
> > >
> > >> Currently the call to device_property_read_u32_array is not error checked
> > >> leading to potential garbage values in the delays array that are then used
> > >> in msleep delays.  Add a sanity check to the property fetching.
> > >>
> > >> Addresses-Coverity: ("Uninitialized scalar variable")
> > >> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > > I have also sent a patch [0] to fix initialize the array.
> > > can you please look at my patch so we can work out which one to use?
> > >
> > > my concern is that the "snps,reset-delays-us" property is optional,
> > > the current dt-bindings documentation states that it's a required
> > > property. in reality it isn't, there are boards (two examples are
> > > mentioned in my patch: [0]) without it.
> > >
> > > so I believe that the resulting behavior has to be:
> > > 1. don't delay if this property is missing (instead of delaying for
> > >    <garbage value> ms)
> > > 2. don't error out if this property is missing
> > >
> > > your patch covers #1, can you please check whether #2 is also covered?
> > > I tested case #2 when submitting my patch and it worked fine (even
> > > though I could not reproduce the garbage values which are being read
> > > on some boards)
in the meantime I have tested your patch.
when I don't set the "snps,reset-delays-us" property then I get the
following error:
  invalid property snps,reset-delays-us

my patch has landed in the meantime: [0]
how should we proceed with your patch?


Martin


[0] https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c?id=84ce4d0f9f55b4f4ca4d4edcbb54a23d9dad1aae