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Wed, 31 Jul 2024 19:16:16 -0700 (PDT) Received: from Laptop-X1 ([2409:8a02:782c:bea0:2ba1:46ac:dba6:9de4]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1fed7c8d376sm127671345ad.18.2024.07.31.19.16.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Jul 2024 19:16:16 -0700 (PDT) Date: Thu, 1 Aug 2024 10:16:11 +0800 From: Hangbin Liu To: Jeongjun Park Cc: jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, nicolas.dichtel@6wind.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+44623300f057a28baf1e@syzkaller.appspotmail.com, syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com Subject: Re: [PATCH net,v2] rtnetlink: fix possible deadlock in team_port_change_check Message-ID: References: <20240731150940.14106-1-aha310510@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240731150940.14106-1-aha310510@gmail.com> On Thu, Aug 01, 2024 at 12:09:40AM +0900, Jeongjun Park wrote: > In do_setlink() , do_set_master() is called when dev->flags does not have > the IFF_UP flag set, so 'team->lock' is acquired and dev_open() is called, > which generates the NETDEV_UP event. This causes a deadlock as it tries to > acquire 'team->lock' again. > > To solve this, we need to unlock 'team->lock' before calling dev_open() > in team_port_add() and then reacquire the lock when dev_open() returns. > Since the implementation acquires the lock in advance when the team > structure is used inside dev_open(), data races will not occur even if it > is briefly unlocked. > > > Reported-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com > Fixes: ec4ffd100ffb ("Revert "net: rtnetlink: Enslave device before bringing it up"") The fixes tag shouldn't be ec4ffd100ffb, as the issue exists before ec4ffd100ffb. I think it should be 3d249d4ca7d0 ("net: introduce ethernet teaming device") Jiri, what do you think? Thanks Hangbin