linux-kernel - Re: [PATCH] iio: common: scmi_iio: use kcalloc() instead of kzalloc()

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: <995cbacb-b01e-4799-84ab-44d58ab32ab7@vivo.com>
Date: Tue, 19 Aug 2025 18:07:53 +0800
From: Qianfeng Rong <rongqianfeng@...o.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Jyoti Bhayana <jbhayana@...gle.com>, Jonathan Cameron <jic23@...nel.org>,
 David Lechner <dlechner@...libre.com>, Nuno Sá
 <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>,
 linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: common: scmi_iio: use kcalloc() instead of kzalloc()


在 2025/8/19 17:46, Andy Shevchenko 写道:
> [You don't often get email from andy.shevchenko@...il.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> On Tue, Aug 19, 2025 at 11:56 AM Qianfeng Rong <rongqianfeng@...o.com> wrote:
>> Replace calls of devm_kzalloc() with devm_kcalloc() in scmi_alloc_iiodev()
>> and scmi_iio_set_sampling_freq_avail() for safer memory allocation with
>> built-in overflow protection.
> While this change is correct...
>
> ...
>
>>          sensor->freq_avail =
>> -               devm_kzalloc(&iio_dev->dev,
>> -                            sizeof(*sensor->freq_avail) *
>> -                                    (sensor->sensor_info->intervals.count * 2),
>> +               devm_kcalloc(&iio_dev->dev,
>> +                            sensor->sensor_info->intervals.count * 2,
> ...I would also switch this to use array_size() instead of explicit
> multiplication as it will check for boundaries that are not static in
> this case.

I don't understand what "will check for boundaries that are not static in
this case" means. Could you explain it to me?

I've experimented with the following command and found that kmalloc_array()
generates fewer instructions than kmalloc(array_size()):
objdump -dSl --prefix-addresses <changed module>.o

> --
> With Best Regards,
> Andy Shevchenko
Best regards,
Qianfeng