linux-kernel - Re: Question on expiring HRtimer in-kernel

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] [day] [month] [year] [list]

Date:   Thu, 3 Mar 2022 23:55:11 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Matti Vaittinen <mazziesaccount@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Sebastian Reichel <sre@...nel.org>,
        Code Kipper <codekipper@...il.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: Question on expiring HRtimer in-kernel

On Thu, Mar 3, 2022 at 1:43 PM Matti Vaittinen <mazziesaccount@...il.com> wrote:

> In any case, I remember few cases where I hit nasty issues because I
> used CLOCK_REALTIME - which (AFAIR) is subject to the time adjustments.
> NTP, GPS-time and so on can make the time tick in a strange way :) I
> guess you would have noticed if time was set when timer did expire.
>
> Anyways, I guess the battery charging should rather be tied CLOCK_MONOTONIC.

That makes a lot of sense, and is what I have learned from the internal
kernel primitives as well, I just assumed the HRTimer was some special
kind of beast.

I'll patch this and run some testing, if it goes away with MONOTONIC
I'll send a patch. Thanks!

Yours,
Linus Walleij