linux-kernel - Re: [PATCH net] rtnetlink: fix possible deadlock in team_port_change

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Message-ID: <20240730165912.67600510@kernel.org>
Date: Tue, 30 Jul 2024 16:59:12 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Jeongjun Park <aha310510@...il.com>
Cc: davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
 idosch@...dia.com, jiri@...nulli.us, amcohen@...dia.com,
 liuhangbin@...il.com, netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 syzbot+b668da2bc4cb9670bf58@...kaller.appspotmail.com
Subject: Re: [PATCH net] rtnetlink: fix possible deadlock in
 team_port_change_check

On Wed, 31 Jul 2024 00:22:10 +0900 Jeongjun Park wrote:
> do_setlink() changes the flag of the device and then enslaves it. However,
> in this case, if the IFF_UP flag is set, the enslavement process calls
> team_add_slave() to acquire 'team->lock', but when dev_open() opens the
> newly enslaved device, the NETDEV_UP event occurs, and as a result,
> a deadlock occurs when team_port_change_check() tries to acquire 
> 'team->lock' again.

You can't change behavior like this, see ec4ffd100ffb396ec
-- 
pw-bot: reject