netdev - Re: [PATCH net-next v2 0/3] net: Avoid ehash lookup races

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Message-ID: <CANn89iKHr_cxcsPG0Oy7SJ9jyZS5zRAgPZL_wy8PSighy+Cy6A@mail.gmail.com>
Date: Tue, 16 Sep 2025 02:02:34 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: luoxuanqiang <xuanqiang.luo@...ux.dev>
Cc: kuniyu@...gle.com, kerneljasonxing@...il.com, davem@...emloft.net, 
	kuba@...nel.org, netdev@...r.kernel.org, 
	Xuanqiang Luo <luoxuanqiang@...inos.cn>
Subject: Re: [PATCH net-next v2 0/3] net: Avoid ehash lookup races

On Tue, Sep 16, 2025 at 1:12 AM luoxuanqiang <xuanqiang.luo@...ux.dev> wrote:
>
>
> 在 2025/9/16 15:30, Eric Dumazet 写道:
> > On Mon, Sep 15, 2025 at 11:47 PM <xuanqiang.luo@...ux.dev> wrote:
> >> From: Xuanqiang Luo <luoxuanqiang@...inos.cn>
> >>
> >> After replacing R/W locks with RCU in commit 3ab5aee7fe84 ("net: Convert
> >> TCP & DCCP hash tables to use RCU / hlist_nulls"), a race window emerged
> >> during the switch from reqsk/sk to sk/tw.
> >>
> >> Now that both timewait sock (tw) and full sock (sk) reside on the same
> >> ehash chain, it is appropriate to introduce hlist_nulls replace
> >> operations, to eliminate the race conditions caused by this window.
> >>
> >> ---
> >> Changes:
> >>    v2:
> >>      * Patch 1
> >>          * Use WRITE_ONCE() to initialize old->pprev.
> >>      * Patch 2&3
> >>          * Optimize sk hashed check. Thanks Kuni for pointing it out!
> >>
> >>    v1: https://lore.kernel.org/all/20250915070308.111816-1-xuanqiang.luo@linux.dev/
> > Note : I think you sent an earlier version, you should have added a
> > link to the discussion,
> > and past feedback/suggestions.
> >
> > Lack of credit is a bit annoying frankly.
> >
> > I will take a look at your series, thanks.
>
> This patch's solution isn't very related to previous ones, so I didn't
> include prior discussions.

This is completely related, aiming to fix the same issue, do not try
to pretend otherwise.

Really, adding more context and acknowledging that reviewers
made suggestions would be quite fair.

This is a difficult series, with a lot of potential bugs, you need to bring
us on board.