Ivan Vecera f0947d0d21 team: protect features update by RCU to avoid deadlock ... Function __team_compute_features() is protected by team->lock mutex when it is called from team_compute_features() used when features of an underlying device is changed. This causes a deadlock when NETDEV_FEAT_CHANGE notifier for underlying device is fired due to change propagated from team driver (e.g. MTU change). It's because callbacks like team_change_mtu() or team_vlan_rx_{add,del}_vid() protect their port list traversal by team->lock mutex. Example (r8169 case where this driver disables TSO for certain MTU values): ... [ 6391.348202] __mutex_lock.isra.6+0x2d0/0x4a0 [ 6391.358602] team_device_event+0x9d/0x160 [team] [ 6391.363756] notifier_call_chain+0x47/0x70 [ 6391.368329] netdev_update_features+0x56/0x60 [ 6391.373207] rtl8169_change_mtu+0x14/0x50 [r8169] [ 6391.378457] dev_set_mtu_ext+0xe1/0x1d0 [ 6391.387022] dev_set_mtu+0x52/0x90 [ 6391.390820] team_change_mtu+0x64/0xf0 [team] [ 6391.395683] dev_set_mtu_ext+0xe1/0x1d0 [ 6391.399963] do_setlink+0x231/0xf50 ... In fact team_compute_features() called from team_device_event() does not need to be protected by team->lock mutex and rcu_read_lock() is sufficient there for port list traversal. Fixes: 3d249d4ca7 ("net: introduce ethernet teaming device") Cc: Saeed Mahameed <saeed@kernel.org> Signed-off-by: Ivan Vecera <ivecera@redhat.com> Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/20210125074416.4056484-1-ivecera@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2021-01-26 17:08:59 -08:00
..
Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
team_mode_activebackup.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
team_mode_broadcast.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
team_mode_loadbalance.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
team_mode_random.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
team_mode_roundrobin.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
team.c	team: protect features update by RCU to avoid deadlock	2021-01-26 17:08:59 -08:00