Re: [PATCH] arm: smp: Avoid false positive CPU hotplug Lockdep-RCU splat

From: Stefan Wiehler
Date: Fri Mar 08 2024 - 05:21:53 EST


> I'm not sure this is a false-positive: if you traverse an RCU-list
> without RCU watching the CPU, then a grace period may pass, the next
> list can be garbage and you can go anywhere from the list. Or am I
> missing something that a CPU hotplug can block a grace period?
Thanks for the feedback! Yes, calling it a false positive is probably not
correct, I will remove that. However, as Russell has explained in a previous
email, the spinlock is fundamental for ASID handling and cannot be removed.

@Russell, I will submit to the patch tracking system then.