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AJvYcCW9ywuvKeVhoNATr7++agpETgjsRkN+aVSLux0tE4VaOB0dIW0jT20/2Y5BCWKYtJ32bpfuIoV7f0nMPgQ4CxbXYlCpIK5lxFhbYQZMPcyZMWqMYOxuK3uFRLQwysqom0Z2IVBv X-Gm-Message-State: AOJu0Yy/QeaSGbOtLyCiCgbZaU0t6XVZyHB6/ISpX9I6vWecf71cQ93+ 0LWZPH00RhV1sX2evljfxjekROPE0ymffF4alNXnTC+lSJxLyybb X-Google-Smtp-Source: AGHT+IFDfhm0K6JoG12J5Rx2/x1IL2tWJEvmqkrUiN32sQcsyQBavttJjBMt0d5//xNr1G/wMaxoIA== X-Received: by 2002:a05:6808:23ca:b0:3d5:fdc5:cfb9 with SMTP id 5614622812f47-3d6b2b24facmr17631436b6e.1.1720018328311; Wed, 03 Jul 2024 07:52:08 -0700 (PDT) Received: from kernelexploit-virtual-machine.localdomain ([121.185.186.233]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-708044b0c5csm10492973b3a.167.2024.07.03.07.52.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Jul 2024 07:52:07 -0700 (PDT) From: Jeongjun Park To: jiri@resnulli.us Cc: syzbot+705c61d60b091ef42c04@syzkaller.appspotmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, Jeongjun Park Subject: [PATCH net] team: Fix ABBA deadlock caused by race in team_del_slave Date: Wed, 3 Jul 2024 23:51:59 +0900 Message-Id: <20240703145159.80128-1-aha310510@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <000000000000ffc5d80616fea23d@google.com> References: <000000000000ffc5d80616fea23d@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org CPU0 CPU1 ---- ---- lock(&rdev->wiphy.mtx); lock(team->team_lock_key#4); lock(&rdev->wiphy.mtx); lock(team->team_lock_key#4); Deadlock occurs due to the above scenario. Therefore, modify the code as shown in the patch below to prevent deadlock. Regards, Jeongjun Park. Reported-and-tested-by: syzbot+705c61d60b091ef42c04@syzkaller.appspotmail.com Fixes: 61dc3461b954 ("team: convert overall spinlock to mutex") Signed-off-by: Jeongjun Park --- drivers/net/team/team_core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) -- diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c index ab1935a4aa2c..3ac82df876b0 100644 --- a/drivers/net/team/team_core.c +++ b/drivers/net/team/team_core.c @@ -1970,11 +1970,12 @@ static int team_add_slave(struct net_device *dev, struct net_device *port_dev, struct netlink_ext_ack *extack) { struct team *team = netdev_priv(dev); - int err; + int err, locked; - mutex_lock(&team->lock); + locked = mutex_trylock(&team->lock); err = team_port_add(team, port_dev, extack); - mutex_unlock(&team->lock); + if (locked) + mutex_unlock(&team->lock); if (!err) netdev_change_features(dev); @@ -1985,11 +1986,12 @@ static int team_add_slave(struct net_device *dev, struct net_device *port_dev, static int team_del_slave(struct net_device *dev, struct net_device *port_dev) { struct team *team = netdev_priv(dev); - int err; + int err, locked; - mutex_lock(&team->lock); + locked = mutex_trylock(&team->lock); err = team_port_del(team, port_dev); - mutex_unlock(&team->lock); + if (locked) + mutex_unlock(&team->lock); if (err) return err;