Subject: Re: [Regression] stress-ng udp-flood causes kernel panic on Ampere Altra

From: Florian Westphal <[email-masked]>
Date: Fri, 1 Jul 2022 22:01:10 +0200

Kajetan Puchalski <[email-masked]> wrote:
> While running the udp-flood test from stress-ng on Ampere Altra (Mt.
> Jade platform) I encountered a kernel panic caused by NULL pointer
> dereference within nf_conntrack.
> 
> The issue is present in the latest mainline (5.19-rc4), latest stable
> (5.18.8), as well as multiple older stable versions. The last working
> stable version I found was 5.15.40.

Do I need a special setup for conntrack?

No crashes after more than one hour of stress-ng on
1. 4 core amd64 Fedora 5.17 kernel
2. 16 core amd64, linux stable 5.17.15
3. 12 core intel, Fedora 5.18 kernel
4. 3 core aarch64 vm, 5.18.7-200.fc36.aarch64

I used standard firewalld ruleset for all of these and manually tuned
conntrack settings to make sure the early evict path (as per backtrace)
gets exercised.