netdev - Re: [PATCH net-next v2] netpoll: Use rtnl_dereference() for npinfo pointer access

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Message-ID: <CANn89i+iQJ70z2P-ZVYq9vbas16wDnBPQdp8fZT6X8qONeovGw@mail.gmail.com>
Date: Fri, 22 Nov 2024 15:46:17 +0100
From: Eric Dumazet <edumazet@...gle.com>
To: Breno Leitao <leitao@...ian.org>
Cc: "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, 
	Michal Kubiak <michal.kubiak@...el.com>, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, kernel-team@...a.com, 
	Herbert Xu <herbert@...dor.apana.org.au>, Jacob Keller <jacob.e.keller@...el.com>
Subject: Re: [PATCH net-next v2] netpoll: Use rtnl_dereference() for npinfo
 pointer access

On Fri, Nov 22, 2024 at 2:18 PM Breno Leitao <leitao@...ian.org> wrote:
>
> In the __netpoll_setup() function, when accessing the device's npinfo
> pointer, replace rcu_access_pointer() with rtnl_dereference(). This
> change is more appropriate, as suggested by Herbert Xu[1].
>
> The function is called with the RTNL mutex held, and the pointer is
> being dereferenced later, so, dereference earlier and just reuse the
> pointer for the if/else.
>
> The replacement ensures correct pointer access while maintaining
> the existing locking and RCU semantics of the netpoll subsystem.
>
> Link: https://lore.kernel.org/lkml/Zz1cKZYt1e7elibV@gondor.apana.org.au/ [1]
> Suggested-by: Herbert Xu <herbert@...dor.apana.org.au>
> Signed-off-by: Breno Leitao <leitao@...ian.org>
> Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>
> Acked-by: Herbert Xu <herbert@...dor.apana.org.au>

Okay, but net-next is currently closed.