linux-kernel - Re: [EXTERNAL] Re: [PATCH] EDAC: update edac printk wrappers to use printk

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:   Wed, 5 May 2021 21:45:01 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Lei Wang (DPLAT)" <Wang.Lei@...rosoft.com>
Cc:     wangglei <wangglei@...il.com>,
        "mchehab@...nel.org" <mchehab@...nel.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "james.morse@....com" <james.morse@....com>,
        "rric@...nel.org" <rric@...nel.org>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Hang Li <hangl@...rosoft.com>,
        "tyhicks@...ux.microsoft.com" <tyhicks@...ux.microsoft.com>,
        Brandon Waller <bwaller@...rosoft.com>
Subject: Re: [EXTERNAL] Re: [PATCH] EDAC: update edac printk wrappers to use
 printk_ratelimited.

Hi Lei,

On Wed, May 05, 2021 at 07:02:14PM +0000, Lei Wang (DPLAT) wrote:
> Hi Boris,

first of all, please do not top-post.

> We found a corner case in production environment that there are ~500
> CE errors per second. The SoC otherwise functions just fine. Making
> printk ratelimited reduced CE error logging to < 20 per second.

If you want to avoid CE logs flooding dmesg, there's a couple of things
you can do:

1. Use drivers/ras/cec.c

2. Do not load EDAC drivers at all since you don't care about the error
reports, apparently.

3. Fix the CE source: replace the DIMMs, etc.

> Though this is just one case so far, we think moving to
> printk_ratelimited could benefit broader use as well, by helping
> control the amount of kernel logging.

No, this will make EDAC driver loading output incomplete when some of
the messages are omitted due to the ratelimiting. And no, this is not
going to happen.

HTH.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette