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1bc4e2b000
batman-adv checks in different situation if a new device is already on top
of a different batman-adv device. This is done by getting the iflink of a
device and all its parent. It assumes that this iflink is always a parent
device in an acyclic graph. But this assumption is broken by devices like
veth which are actually a pair of two devices linked to each other. The
recursive check would therefore get veth0 when calling dev_get_iflink on
veth1. And it gets veth0 when calling dev_get_iflink with veth1.
Creating a veth pair and loading batman-adv freezes parts of the system
ip link add veth0 type veth peer name veth1
modprobe batman-adv
An RCU stall will be detected on the system which cannot be fixed.
INFO: rcu_sched self-detected stall on CPU
1: (5264 ticks this GP) idle=3e9/140000000000001/0
softirq=144683/144686 fqs=5249
(t=5250 jiffies g=46 c=45 q=43)
Task dump for CPU 1:
insmod R running task 0 247 245 0x00000008
ffffffff8151f140 ffffffff8107888e ffff88000fd141c0 ffffffff8151f140
0000000000000000 ffffffff81552df0 ffffffff8107b420 0000000000000001
ffff88000e3fa700 ffffffff81540b00 ffffffff8107d667 0000000000000001
Call Trace:
<IRQ> [<ffffffff8107888e>] ? rcu_dump_cpu_stacks+0x7e/0xd0
[<ffffffff8107b420>] ? rcu_check_callbacks+0x3f0/0x6b0
[<ffffffff8107d667>] ? hrtimer_run_queues+0x47/0x180
[<ffffffff8107cf9d>] ? update_process_times+0x2d/0x50
[<ffffffff810873fb>] ? tick_handle_periodic+0x1b/0x60
[<ffffffff810290ae>] ? smp_trace_apic_timer_interrupt+0x5e/0x90
[<ffffffff813bbae2>] ? apic_timer_interrupt+0x82/0x90
<EOI> [<ffffffff812c3fd7>] ? __dev_get_by_index+0x37/0x40
[<ffffffffa0031f3e>] ? batadv_hard_if_event+0xee/0x3a0 [batman_adv]
[<ffffffff812c5801>] ? register_netdevice_notifier+0x81/0x1a0
[...]
This can be avoided by checking if two devices are each others parent and
stopping the check in this situation.
Fixes:
|
||
|---|---|---|
| .. | ||
| 6lowpan | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| batman-adv | ||
| bluetooth | ||
| bridge | ||
| caif | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| dccp | ||
| decnet | ||
| dns_resolver | ||
| dsa | ||
| ethernet | ||
| hsr | ||
| ieee802154 | ||
| ipv4 | ||
| ipv6 | ||
| ipx | ||
| irda | ||
| iucv | ||
| key | ||
| l2tp | ||
| l3mdev | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| mac802154 | ||
| mpls | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| netrom | ||
| nfc | ||
| openvswitch | ||
| packet | ||
| phonet | ||
| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| sunrpc | ||
| switchdev | ||
| tipc | ||
| unix | ||
| vmw_vsock | ||
| wimax | ||
| wireless | ||
| x25 | ||
| xfrm | ||
| compat.c | ||
| Kconfig | ||
| Makefile | ||
| socket.c | ||
| sysctl_net.c | ||