Messages in this thread | | | Date | Mon, 6 Dec 2021 23:29:53 +0100 | From | Marek Behún <> | Subject | Re: [PATCH] net: dsa: mv88e6xxx: initialize return variable on declaration |
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On Mon, 6 Dec 2021 14:21:03 +0100 Andrew Lunn <andrew@lunn.ch> wrote:
> On Mon, Dec 06, 2021 at 04:32:19PM +0500, Ameer Hamza wrote: > > Uninitialized err variable defined in mv88e6393x_serdes_power > > function may cause undefined behaviour if it is called from > > mv88e6xxx_serdes_power_down context. > > > > Addresses-Coverity: 1494644 ("Uninitialized scalar variable") > > > > Signed-off-by: Ameer Hamza <amhamza.mgc@gmail.com> > > --- > > drivers/net/dsa/mv88e6xxx/serdes.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c > > index 55273013bfb5..33727439724a 100644 > > --- a/drivers/net/dsa/mv88e6xxx/serdes.c > > +++ b/drivers/net/dsa/mv88e6xxx/serdes.c > > @@ -1507,7 +1507,7 @@ int mv88e6393x_serdes_power(struct mv88e6xxx_chip *chip, int port, int lane, > > bool on) > > { > > u8 cmode = chip->ports[port].cmode; > > - int err; > > + int err = 0; > > > > if (port != 0 && port != 9 && port != 10) > > return -EOPNOTSUPP; > > Hi Marek > > This warning likely comes from cmode not being a SERDES mode, and that > is not handles in the switch statementing. Do we want an > > default: > err = EINVAL; > > ? > > Andrew
Hi Andrew,
currently all the .serdes_power() methods return 0 for non-serdes ports. This is because the way it is written, these methods are not called if there is not a serdes lane for a given port.
For this issue with err variable undefined, to fix it we should simply set int err=0 at the beginning of mv88e6393x_serdes_power(), to make it behave like other serdes_power() methods do in serdes.c.
But a refactor may be needed for serdes_power() methods, at least because they are a little weird. But it should be unrelated to this fix.
In serdes.h we have static inline functions mv88e6xxx_serdes_power_up(chip, port, lane) mv88e6xxx_serdes_power_down(chip, port, lane)
(These simply call the serdes_power() method of chip ops, with additional boolean argument to specify powerup/powerdown. Also for these we first need to determine lane for a port. If lane does not exists, these should not be called.)
In chip.c we have function mv88e6xxx_serdes_power(chip, port, on)
(This finds if the port has a lane, and if so, calls, if on=true mv88e6xxx_serdes_power_up() from serdes.h, and then mv88e6xxx_serdes_irq_request() also from serdes.h
and if on=false, calls _irq_free() & _serdes_power_down() )
So if I call mv88e6xxx_serdes_power(chip, port, true) it goes mv88e6xxx_serdes_power_up(chip, port, lane) chip->info->ops->serdes_power(chip, port, lane, true) so the `on` argument is used in some places, but in other places there are two functions instead.
Which I find a little weird.
Marek
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