linux-kernel - Re: amd iommu: rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 8 jiffies s: 113 root: 0x1/.

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]

Message-ID: <20251204144505.GCaTGecavu-E56OR8V@fat_crate.local>
Date: Thu, 4 Dec 2025 15:45:05 +0100
From: Borislav Petkov <bp@...en8.de>
To: "Paul E. McKenney" <paulmck@...nel.org>
Cc: iommu@...ts.linux.dev, Joerg Roedel <joro@...tes.org>,
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
	Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
	linux-kernel@...r.kernel.org
Subject: Re: amd iommu: rcu: INFO: rcu_preempt detected expedited stalls on
 CPUs/tasks: { 0-.... } 8 jiffies s: 113 root: 0x1/.

On Wed, Dec 03, 2025 at 09:16:37AM -0800, Paul E. McKenney wrote:
> Or to some value that works for you.  But if you are not looking to be
> an expedited RCU CPU stall-warning pioneer, yes, setting it to zero is
> a good approach.
> 
> If you would like to be a more sane pioneer, setting it to (say) 11000
> (or 11 seconds) could be appropriate.  But what fun is sanity?  ;-)

Oh, I have a lot of excitement even without RCU experiments. :-P

But if you need me to try things, lemme know.

For now I've simply reset the values as to what defconfig sets them to:

CONFIG_RCU_CPU_STALL_TIMEOUT=21
CONFIG_RCU_EXP_CPU_STALL_TIMEOUT=0

Thx.

-- 
Regards/Gruss,
    Boris.

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