mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: Lucas Stach <l.stach@pengutronix.de>
To: Oleksij Rempel <linux@rempel-privat.de>, barebox@lists.infradead.org
Subject: Re: [PATCH v1 2/9] pinctrl: tegra30: fix "Possible null pointer dereference: group" warning
Date: Wed, 21 Nov 2018 10:16:58 +0100	[thread overview]
Message-ID: <1542791818.23859.1.camel@pengutronix.de> (raw)
In-Reply-To: <20181120200714.3692-3-linux@rempel-privat.de>

Am Dienstag, den 20.11.2018, 21:07 +0100 schrieb Oleksij Rempel:
> The code is correct but it takes more seconds for me to understand.
> And static code analyzer do not understand it at all.
> 
> > Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
> ---
>  drivers/pinctrl/pinctrl-tegra30.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-tegra30.c b/drivers/pinctrl/pinctrl-tegra30.c
> index d9b49c57d..ffb04eebb 100644
> --- a/drivers/pinctrl/pinctrl-tegra30.c
> +++ b/drivers/pinctrl/pinctrl-tegra30.c
> @@ -658,8 +658,8 @@ static int pinctrl_tegra30_set_drvstate(struct pinctrl_tegra30 *ctrl,
> >  			break;
> >  		}
> >  	}
> > -	/* if no matching drivegroup is found */
> > -	if (i == ctrl->drvdata->num_drvgrps)
> +
> > +	if (!group)
> >  		return 0;

Huh? This is a pretty standard idiom in C codebases to check if we
broke out of a loop early.

Actually this change breaks the code, as this check is inside of an
outer loop that doesn't reinitialize the group variable. So while the
code as-is correctly checks if a group was found in the current
iteration of the outer loop, after this patch it also matches a group
that was found on a previous iteration of the outer loop.

This is a prime example where static checker warnings can prompt wrong
fixes. Frankly codacy should smart up to correctly analyze the
controlflow interdependency.

Sascha, please drop this patch.

Regards,
Lucas

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

  reply	other threads:[~2018-11-21  9:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-20 20:07 [PATCH v1 0/9] random fixes Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 1/9] net: e1000: fix "Uninitialized variable: phy_data" warning Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 2/9] pinctrl: tegra30: fix "Possible null pointer dereference: group" warning Oleksij Rempel
2018-11-21  9:16   ` Lucas Stach [this message]
2018-11-21  9:40     ` Oleksij Rempel
2018-11-21 10:01       ` Lucas Stach
2018-11-20 20:07 ` [PATCH v1 3/9] fs: closedir: remove uninitialized variable ret Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 4/9] fs: fix possible null pointer dereference of base Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 5/9] mfd: da9063: fix wrong NULL pointer test Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 6/9] usb: at91_udc: remove useless NULL check Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 7/9] mtd: atmel_nand: remove erroneous case Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 8/9] usb: musb: fix possible out of bounds access Oleksij Rempel
2018-11-20 20:07 ` [PATCH v1 9/9] lib: lodepng: remove useless test Oleksij Rempel
2018-11-21  8:08 ` [PATCH v1 0/9] random fixes Sascha Hauer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1542791818.23859.1.camel@pengutronix.de \
    --to=l.stach@pengutronix.de \
    --cc=barebox@lists.infradead.org \
    --cc=linux@rempel-privat.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox