linux-kernel - Re: [PATCH] irq: clear kstat

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, 6 Feb 2009 14:00:05 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] irq: clear kstat_irqs

On Fri, 06 Feb 2009 13:50:47 -0800
Yinghai Lu <yinghai@...nel.org> wrote:

> +void clear_kstat_irqs(struct irq_desc *desc)
> +{
> +	unsigned long bytes;

size_t would be more formally correct.

> +	char *ptr;
> +
> +	ptr = (char *)desc->kstat_irqs;
> +	/* Compute how many bytes we need to clear */
> +	bytes = nr_cpu_ids * sizeof(unsigned int);

This is fragile.  For example, if someone changes ->kstat_irqs to long
then this code will secretly and subtly break.

If it used sizeof(*(desc->kstat_irqs)) then everything would magically
continue to work.

> +	memset(ptr, 0, bytes);
> +}

The whole function could be written as

	memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));

--
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/