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3715a00855
When a peer MEP is being deleted, cancel_delayed_work_sync() is called
on ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in
softirq context under rcu_read_lock (without RTNL) and can re-schedule
ccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync()
returning and kfree_rcu() being called.
The following is a simple race scenario:
cpu0 cpu1
mep_delete_implementation()
cancel_delayed_work_sync(ccm_rx_dwork);
br_cfm_frame_rx()
// peer_mep still in hlist
if (peer_mep->ccm_defect)
ccm_rx_timer_start()
queue_delayed_work(ccm_rx_dwork)
hlist_del_rcu(&peer_mep->head);
kfree_rcu(peer_mep, rcu);
ccm_rx_work_expired()
// on freed peer_mep
To prevent this, cancel_delayed_work_sync() is replaced with
disable_delayed_work_sync() in both peer MEP deletion paths, so
that subsequent queue_delayed_work() calls from br_cfm_frame_rx()
are silently rejected.
The cc_peer_disable() helper retains cancel_delayed_work_sync()
because it is also used for the CC enable/disable toggle path where
the work must remain re-schedulable.
Fixes:
|
||
|---|---|---|
| .. | ||
| netfilter | ||
| br_arp_nd_proxy.c | ||
| br_cfm_netlink.c | ||
| br_cfm.c | ||
| br_device.c | ||
| br_fdb.c | ||
| br_forward.c | ||
| br_if.c | ||
| br_input.c | ||
| br_ioctl.c | ||
| br_mdb.c | ||
| br_mrp_netlink.c | ||
| br_mrp_switchdev.c | ||
| br_mrp.c | ||
| br_mst.c | ||
| br_multicast_eht.c | ||
| br_multicast.c | ||
| br_netfilter_hooks.c | ||
| br_netfilter_ipv6.c | ||
| br_netlink_tunnel.c | ||
| br_netlink.c | ||
| br_nf_core.c | ||
| br_private_cfm.h | ||
| br_private_mcast_eht.h | ||
| br_private_mrp.h | ||
| br_private_stp.h | ||
| br_private_tunnel.h | ||
| br_private.h | ||
| br_stp_bpdu.c | ||
| br_stp_if.c | ||
| br_stp_timer.c | ||
| br_stp.c | ||
| br_switchdev.c | ||
| br_sysfs_br.c | ||
| br_sysfs_if.c | ||
| br_vlan_options.c | ||
| br_vlan_tunnel.c | ||
| br_vlan.c | ||
| br.c | ||
| Kconfig | ||
| Makefile | ||