linux-kernel - Re: [PATCH V2 1/6] PM / OPP: Free resources and properly return error on failure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150811144345.GN5180@mwanda>
Date:	Tue, 11 Aug 2015 17:43:45 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	Rafael Wysocki <rjw@...ysocki.net>, nm@...com,
	sboyd@...eaurora.org, linaro-kernel@...ts.linaro.org,
	linux-pm@...r.kernel.org, khilman@...aro.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Len Brown <len.brown@...el.com>,
	open list <linux-kernel@...r.kernel.org>,
	Pavel Machek <pavel@....cz>
Subject: Re: [PATCH V2 1/6] PM / OPP: Free resources and properly return
 error on failure

On Tue, Aug 11, 2015 at 04:04:34PM +0530, Viresh Kumar wrote:
> _of_init_opp_table_v2() isn't freeing up resources on some errors and
> the error values returned are also not correct always.
> 
> This fixes following problems:
> - Return -ENOENT, if no entries are found in the table.
> - Use IS_ERR() to properly check return value of _find_device_opp().
> - Return error value with PTR_ERR() in above case.
> - Free table if _find_device_opp() fails.
> 
> Fixes: 274659029c9d ("PM / OPP: Add support to parse operating-points-v2" bindings")
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/base/power/opp.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index 204c6c945168..bcbd92c3b717 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -1323,28 +1323,29 @@ static int _of_init_opp_table_v2(struct device *dev,
>  		if (ret) {
>  			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
>  				ret);
> -			break;
> +			goto free_table;
>  		}
>  	}
>  
>  	/* There should be one of more OPP defined */
> -	if (WARN_ON(!count))
> +	if (WARN_ON(!count)) {
> +		ret = -ENOENT;
>  		goto put_opp_np;
> +	}

This is weird to me, because we are going backwards.  What happens if
we goto free_table without adding anything?  I suspect it's fine, but if
it's a bug then this code still has problems.

What about if we only increment count when _opp_add_static_v2()
succeeds, and change it back to the original where we break, check
count, then check ret.  That way we don't need to know the details of
free_table to see that the code is correct.

regards,
dan carpenter

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/