linux-kernel - Re: [RFC PATCH] iio: ak8975: Make sure chipset is always initialized

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <CAEnQRZAfRJ+-1x_ZgRAC2Kkr2js4EQB1xA6gTJ5n0uCAZS4y2g@mail.gmail.com>
Date:	Mon, 19 Jan 2015 18:49:18 +0200
From:	Daniel Baluta <daniel.baluta@...el.com>
To:	"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
Cc:	"Baluta, Daniel" <daniel.baluta@...el.com>,
	"lars@...afoo.de" <lars@...afoo.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"knaack.h@....de" <knaack.h@....de>,
	"jic23@...nel.org" <jic23@...nel.org>,
	"Purdila, Octavian" <octavian.purdila@...el.com>,
	"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
	"Westerberg, Mika" <mika.westerberg@...el.com>,
	"pmeerw@...erw.net" <pmeerw@...erw.net>,
	"beomho.seo@...sung.com" <beomho.seo@...sung.com>,
	"gwendal@...omium.org" <gwendal@...omium.org>
Subject: Re: [RFC PATCH] iio: ak8975: Make sure chipset is always initialized

On Mon, Jan 19, 2015 at 6:44 PM, Pandruvada, Srinivas
<srinivas.pandruvada@...el.com> wrote:
> On Mon, 2015-01-19 at 16:40 +0200, Daniel Baluta wrote:
>> Hello,
>>
>> On Sat, Dec 20, 2014 at 11:29 PM, Pandruvada, Srinivas
>> <srinivas.pandruvada@...el.com> wrote:
>> > +Mika
>> >
>> > On Sat, 2014-12-20 at 13:26 -0800, Srinivas Pandruvada wrote:
>> >> On Sat, 2014-12-20 at 00:25 +0200, Daniel Baluta wrote:
>> >> > On Sat, Dec 20, 2014 at 12:16 AM, Hartmut Knaack <knaack.h@....de> wrote:
>> >> > > Daniel Baluta schrieb am 18.12.2014 um 18:16:
>> >> > >> When using ACPI, if acpi_match_device fails then chipset enum will be
>> >> > >> uninitialized and &ak_def_array[chipset] will point to some bad address.
>> >> > >>
>> >> I am missing something. You are enumerated over i2c device, which was
>> >> created from ACPI PNP resource. There is a valid handle or and the
>> >> device has an ACPI companion at the least. If this failing, I have to
>> >> check the code for acpi i2c.
>> >> Can you check why this check failed? We may have bug in i2c handling.
>>
>> You are right about this. Under normal circumstances, if probe is called
>> then acpi_match_device will not fail. I even tried to remove the
>> device after probe
>> but before acpi_match_device, anyhow acpi_match_device was still successful :)
>>
>> This is more a matter of code correctness.
>>
>> In ak8975_match_acpi_device we have:
>>
>> »       const struct acpi_device_id *id;
>>
>> »       id = acpi_match_device(dev->driver->acpi_match_table, dev);
>> »       if (!id)
>> »       »       return NULL;
>> »       *chipset = (int)id->driver_data;
>>
>> Compiler complains on the fact that chipset might be uninitialized
>> if this returns NULL, and we shouldn't ignore this warning even this case
>> will never happen.
>>
> Will this fix?
> data->chipset = AK8975;
> before
> ak8975_match_acpi_device(&client->dev, &data->chipset);
>

Yes, this is done in the original patch:

+       *chipset = AK_MAX_TYPE;

.. and fixes the warning.

Daniel.
--
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/