linux-kernel - Re: [PATCH v2] printk: add option to print cpu id

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]

Date:	Fri, 3 Aug 2012 11:51:13 +0200
From:	Kay Sievers <kay@...y.org>
To:	Nikunj A Dadhania <nikunj@...ux.vnet.ibm.com>
Cc:	Vikram Pandita <vikram.pandita@...com>, gregkh@...uxfoundation.org,
	linux-kernel@...r.kernel.org,
	Mike Turquette <mturquette@...aro.org>,
	Vimarsh Zutshi <vimarsh.zutshi@...il.com>
Subject: Re: [PATCH v2] printk: add option to print cpu id

On Fri, Aug 3, 2012 at 11:43 AM, Nikunj A Dadhania
<nikunj@...ux.vnet.ibm.com> wrote:
> On Fri, 3 Aug 2012 02:16:18 -0700, Vikram Pandita <vikram.pandita@...com> wrote:

>> +static size_t print_cpuid(u8 cpuid, char *buf)
>> +{
>> +
>> +     if (!printk_cpuid)
>> +             return 0;
>> +
>> +     if (!buf)
>> +             return 4;
>> +

> Firstly, why this magic number?
> Secondly, if buf is NULL, why should you increment?

The !buffer logic is used when we only calculate the size of the
output buffer, but do not print to it. It's just an optimization. And
yes, the number returned should match the number of chars that would
have been printed, so this does not look right.

Kay
--
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/