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From: Eric Dumazet <edumazet@google.com>
To: Stanislav Fomichev <sdf@fomichev.me>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
	 pabeni@redhat.com, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,  netfilter-devel@vger.kernel.org,
	coreteam@netfilter.org, horms@kernel.org,  corbet@lwn.net,
	andrew+netdev@lunn.ch, pablo@netfilter.org,
	 kadlec@netfilter.org
Subject: Re: [PATCH net-next] net: revert to lockless TC_SETUP_BLOCK and TC_SETUP_FT
Date: Sat, 8 Mar 2025 07:41:28 +0100	[thread overview]
Message-ID: <CANn89iLV6mLh8mWhYket7gBWTX+3TcCrJDA4EU5YU4ebV2nPYw@mail.gmail.com> (raw)
In-Reply-To: <20250308044726.1193222-1-sdf@fomichev.me>

On Sat, Mar 8, 2025 at 5:47 AM Stanislav Fomichev <sdf@fomichev.me> wrote:
>
> There is a couple of places from which we can arrive to ndo_setup_tc
> with TC_SETUP_BLOCK/TC_SETUP_FT:
> - netlink
> - netlink notifier
> - netdev notifier
>
> Locking netdev too deep in this call chain seems to be problematic
> (especially assuming some/all of the call_netdevice_notifiers
> NETDEV_UNREGISTER) might soon be running with the instance lock).
> Revert to lockless ndo_setup_tc for TC_SETUP_BLOCK/TC_SETUP_FT. NFT
> framework already takes care of most of the locking. Document
> the assumptions.
>


>
> Fixes: c4f0f30b424e ("net: hold netdev instance lock during nft ndo_setup_tc")
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>

I think you forgot to mention syzbot.

Reported-by: syzbot+0afb4bcf91e5a1afdcad@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/67cb88d1.050a0220.d8275.022d.GAE@google.com/T/#u

Thanks.

  reply	other threads:[~2025-03-08  6:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-08  4:47 [PATCH net-next] net: revert to lockless TC_SETUP_BLOCK and TC_SETUP_FT Stanislav Fomichev
2025-03-08  6:41 ` Eric Dumazet [this message]
2025-03-08 17:08   ` Stanislav Fomichev
2025-03-12 12:43 ` Simon Horman
2025-03-12 20:20 ` patchwork-bot+netdevbpf

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