RE: [PATCH] NetCP: Deletion of unnecessary checks before two function calls

Kwok, WingMan
2015-02-05T15:51:06Z

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Dan,

Thanks. We'll look into it and send a patch soon.

Regards,
WingMan

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
> Sent: Thursday, February 05, 2015 7:02 AM
> To: Kwok, WingMan
> Cc: SF Markus Elfring; Karicheri, Muralidharan; Kwok, WingMan;
> netdev@vger.kernel.org; LKML; kernel-janitors@vger.kernel.org; Julia Lawall
> Subject: Re: [PATCH] NetCP: Deletion of unnecessary checks before two
> function calls
>
> Hi Wingman,
>
> There are some bugs in this error handling.
>
> On Tue, Feb 03, 2015 at 08:22:23PM +0100, SF Markus Elfring wrote:
> > diff --git a/drivers/net/ethernet/ti/netcp_ethss.c
> b/drivers/net/ethernet/ti/netcp_ethss.c
> > index fa1041a..cbd6dde 100644
> > --- a/drivers/net/ethernet/ti/netcp_ethss.c
> > +++ b/drivers/net/ethernet/ti/netcp_ethss.c
> > @@ -2010,12 +2010,10 @@ static int gbe_probe(struct netcp_device
> *netcp_device, struct device *dev,
> > quit:
> > if (gbe_dev->hw_stats)
> > devm_kfree(dev, gbe_dev->hw_stats);
> > - if (gbe_dev->ale)
> > - cpsw_ale_destroy(gbe_dev->ale);
> > + cpsw_ale_destroy(gbe_dev->ale);
> > if (gbe_dev->ss_regs)
> > devm_iounmap(dev, gbe_dev->ss_regs);
> > - if (interfaces)
> > - of_node_put(interfaces);
> > + of_node_put(interfaces);
> ^^^^^^^^^^
> "interfaces" is sometimes unintialized in this code. I don't know why
> GCC doesn't catch this... :(
>
> This is a "one rrr bug", which is caused because you just have one error
> label "quit" which handles all the error handling. Please read my
> Google+ comment on error handling.
>
> https://plus.google.com/106378716002406849458/posts/dnanfhQ4mHQ
>
> > devm_kfree(dev, gbe_dev);
> ^^^^^^^^^^^^^^^^^^^^^^^^
> This is not the right way to use the devm_ interface. These things are
> freed automatically on error or when we are done with them. This driver
> is double freeing pretty much everything. Grep for devm_kfree() and
> fix everything.
>
> I don't know why kbuild didn't catch this...
>
> regards
> dan carpenter

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