Re: [EXTERNAL] Re: [PATCH v3 0/2] net/mana: add device reset support

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 28 May 2026 07:30:03 +0000
Wei Hu <weh@microsoft.com> wrote:

> >    so they are invisible to rte_rcu_qsbr_check in the primary, and
> >    the secondary MP handler (mana_mp_reset_enter) does not call
> >    qsbr_check at all -- it just sets db_page = NULL and munmaps.
> > 
> >    The dev_state check at the top of secondary tx_burst is racy:
> >    the page can be munmapped after the in-loop read of db_page but
> >    before the doorbell write at the bottom.  The "All secondary
> >    threads are quiescent" log line in mana_mp_reset_enter is not
> >    true.
> > 
> >    The secondary needs a real reader-side primitive -- its own
> >    qsbr with secondary lcore registration, or an rwlock the MP
> >    handler takes before munmap.
> >   
> 
> Thanks for the v3 review, @Stephen. I will send out v4 to incorporate most
> of the review comments except for this one. 
> 
> The review on this point is not correct. Here I am providing analysis from
>  AI and my own test results to show why.
> 
> The concern is that "rte_rcu_qsbr_thread_register is only called
> from mana_dev_configure, which the secondary never runs", so
> secondary tids are unregistered and invisible to rte_rcu_qsbr_check.


Thanks, I have become way to familiar with AI reaching false conclusions.