netdev - Re: [PATCH net] vrf: Fix lockdep splat in output path

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Message-ID: <CANn89iJKV1pAdwLQ4p2nbFhHnwLW7BH7rzU75-+sVgky5fUvbQ@mail.gmail.com>
Date: Mon, 17 Jul 2023 18:20:06 +0200
From: Eric Dumazet <edumazet@...gle.com>
To: Ido Schimmel <idosch@...dia.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org, 
	pabeni@...hat.com, dsahern@...nel.org, naresh.kamboju@...aro.org
Subject: Re: [PATCH net] vrf: Fix lockdep splat in output path

On Sat, Jul 15, 2023 at 5:37 PM Ido Schimmel <idosch@...dia.com> wrote:
>
> Cited commit converted the neighbour code to use the standard RCU
> variant instead of the RCU-bh variant, but the VRF code still uses
> rcu_read_lock_bh() / rcu_read_unlock_bh() around the neighbour lookup
> code in its IPv4 and IPv6 output paths, resulting in lockdep splats
> [1][2]. Can be reproduced using [3].
>
> Fix by switching to rcu_read_lock() / rcu_read_unlock().

We might have other bugs like that.

We should get rid of all rcu_read_lock_bh()

Reviewed-by: Eric Dumazet <edumazet@...gle.com>

Thanks.