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  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, 14 Feb 2020 01:35:58 +0100
From:   Thomas Gleixner <>
To:     Ionela Voinescu <>,,,,,,,,,,
Subject: Re: [PATCH v3 7/7] clocksource/drivers/arm_arch_timer: validate arch_timer_rate

Ionela Voinescu <> writes:

> From: Valentin Schneider <>
> Using an arch timer with a frequency of less than 1MHz can result in an
> incorrect functionality of the system which assumes a reasonable rate.
> One example is the use of activity monitors for frequency invariance
> which uses the rate of the arch timer as the known rate of the constant
> cycle counter in computing its ratio compared to the maximum frequency
> of a CPU. For arch timer frequencies less than 1MHz this ratio could
> end up being 0 which is an invalid value for its use.
> Therefore, warn if the arch timer rate is below 1MHz which contravenes
> the recommended architecture interval of 1 to 50MHz.
> Signed-off-by: Ionela Voinescu <>

So this patch is from Valentin. Where is his Signed-off-by?

> +static int validate_timer_rate(void)
> +{
> +	if (!arch_timer_rate)
> +		return -EINVAL;
> +
> +	/* Arch timer frequency < 1MHz can cause trouble */
> +	WARN_ON(arch_timer_rate < 1000000);

This does not make sense to me. If the rate is out of bounds then why
warn an just continue instead of making it fail?



Powered by blists - more mailing lists