Re: [RFC PATCH net-next] netpoll: hold RCU while walking napi_list

[Jakub Kicinski]

On Mon, 29 Jun 2026 04:17:10 -0700 Breno Leitao wrote:
> > Sure, sorry for not including it in the RFC.  The warning was from the
> > reviewed reproducer used for the CONFIG_PROVE_RCU_LIST triage, not from
> > a production crash.  The relevant part of the dmesg is:  
> 
> Reading it, it does not come from the kernel's netpoll code at
> all -- it comes from an out-of-tree module (!?)

Yes, like Breno says, we need an in-kernel path that can trigger the
issue. Out-of-tree reproducers can be useful to validate the fix, but
they are not useful to prove that a problem actually exists.

We try to avoid defensive programming in the kernel.