Affected: Linux, Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

In the Linux kernel, the following vulnerability has been resolved:

team: prevent adding a device which is already a team device lower

Prevent adding a device which is already a team device lower, e.g. adding veth0 if vlan1 was already added and veth0 is a lower of vlan1.

This is not useful in practice and can lead to recursive locking:

$ ip link add veth0 type veth peer name veth1 $ ip link set veth0 up $ ip link set veth1 up $ ip link add link veth0 name veth0.1 type vlan protocol 802.1Q id 1 $ ip link add team0 type team $ ip link set veth0.1 down $ ip link set veth0.1 master team0 team0: Port device veth0.1 added $ ip link set veth0 down $ ip link set veth0 master team0

============================================ WARNING: possible recursive locking detected 6.13.0-rc2-virtme-00441-ga14a429069bb #46 Not tainted -------------------------------------------- ip/7684 is trying to acquire lock: ffff888016848e00 (team->team_lock_key){+.+.}-{4:4}, at: team_device_event (drivers/net/team/team_core.c:2928 drivers/net/team/team_core.c:2951 drivers/net/team/team_core.c:2973)

but task is already holding lock: ffff888016848e00 (team->team_lock_key){+.+.}-{4:4}, at: team_add_slave (drivers/net/team/team_core.c:1147 drivers/net/team/team_core.c:1977)

other info that might help us debug this: Possible unsafe locking scenario:

CPU0 ---- lock(team->team_lock_key); lock(team->team_lock_key);

*** DEADLOCK ***

May be due to missing lock nesting notation

2 locks held by ip/7684:

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