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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Breno Leitao <leitao@debian.org>
Cc: Jakub Kicinski <kuba@kernel.org>,
	andrii@kernel.org, ast@kernel.org,
	syzbot <syzbot+08811615f0e17bc6708b@syzkaller.appspotmail.com>,
	bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net,
	eddyz87@gmail.com, haoluo@google.com, hawk@kernel.org,
	john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org,
	linux-kernel@vger.kernel.org, martin.lau@linux.dev,
	netdev@vger.kernel.org, sdf@fomichev.me, song@kernel.org,
	syzkaller-bugs@googlegroups.com, yonghong.song@linux.dev
Subject: Re: [PATCH net-net] tun: Assign missing bpf_net_context.
Date: Thu, 12 Sep 2024 15:33:09 +0200	[thread overview]
Message-ID: <20240912133309.FA7Uul13@linutronix.de> (raw)
In-Reply-To: <20240912-hypnotic-messy-leopard-f1d2b0@leitao>

On 2024-09-12 06:17:55 [-0700], Breno Leitao wrote:
> Hello Sabastian,
Hi Breno,

> > This origins in netkit_xmit(). If my memory serves me, then Daniel told
> > me that netkit is not doing any redirect and therefore does not need
> > "this". This must have been during one of the first "designs"/ versions. 
> 
> Right, I've seen several crashes related to this, and in all of them it
> is through netkit_xmit() -> netkit_run() ->  bpf_prog_run()

Looking at this again, NETKIT_REDIRECT invokes skb_do_redirect() which
is accessing the per-CPU variables/ context from the very first day.
So I must have misunderstood something.

> > If you are saying, that this is possible then something must be done.
> > Either assign a context or reject the bpf program.
> 
> If we want to assign a context, do you meant something like the
> following?

Yes, correct. And I think that we do want the context here.
Feel free to add
  Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
if you post.

Sebastian

  parent reply	other threads:[~2024-09-12 13:33 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-01 20:19 [syzbot] [net?] [bpf?] general protection fault in dev_map_redirect syzbot
2024-07-02 18:40 ` Jakub Kicinski
2024-07-03 12:27   ` [PATCH net-net] tun: Assign missing bpf_net_context Sebastian Andrzej Siewior
2024-07-03 19:01     ` Jakub Kicinski
2024-07-03 19:21       ` Sebastian Andrzej Siewior
2024-07-04 10:14         ` [PATCH v2 " Sebastian Andrzej Siewior
2024-07-04 14:24           ` Jakub Kicinski
2024-07-04 14:48             ` [PATCH v3 net-next] " Sebastian Andrzej Siewior
2024-07-06  0:10               ` patchwork-bot+netdevbpf
2024-09-12 12:06       ` [PATCH net-net] " Breno Leitao
2024-09-12 12:28         ` Sebastian Andrzej Siewior
2024-09-12 13:17           ` Breno Leitao
2024-09-12 13:32             ` Vadim Fedorenko
2024-09-12 14:19               ` Breno Leitao
2024-09-12 14:30                 ` Sebastian Andrzej Siewior
2024-09-12 14:40                   ` Breno Leitao
2024-09-12 13:33             ` Sebastian Andrzej Siewior [this message]
2024-09-12 15:03             ` Daniel Borkmann
2024-09-16 10:19               ` Sebastian Andrzej Siewior
2024-09-12 14:24           ` Toke Høiland-Jørgensen
2024-07-06  6:21 ` [syzbot] [bpf?] [net?] general protection fault in dev_map_redirect syzbot
2024-07-06 13:13   ` Sebastian Andrzej Siewior
2024-07-06 13:38     ` syzbot

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