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![]() Rajendra reported a kernel panic when a link was taken down:
[ 6870.263084] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
[ 6870.271856] IP: [<ffffffff8efc5764>] __ipv6_ifa_notify+0x154/0x290
<snip>
[ 6870.570501] Call Trace:
[ 6870.573238] [<ffffffff8efc58c6>] ? ipv6_ifa_notify+0x26/0x40
[ 6870.579665] [<ffffffff8efc98ec>] ? addrconf_dad_completed+0x4c/0x2c0
[ 6870.586869] [<ffffffff8efe70c6>] ? ipv6_dev_mc_inc+0x196/0x260
[ 6870.593491] [<ffffffff8efc9c6a>] ? addrconf_dad_work+0x10a/0x430
[ 6870.600305] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.606732] [<ffffffff8ea93a7a>] ? process_one_work+0x18a/0x430
[ 6870.613449] [<ffffffff8ea93d6d>] ? worker_thread+0x4d/0x490
[ 6870.619778] [<ffffffff8ea93d20>] ? process_one_work+0x430/0x430
[ 6870.626495] [<ffffffff8ea99dd9>] ? kthread+0xd9/0xf0
[ 6870.632145] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.638573] [<ffffffff8ea99d00>] ? kthread_park+0x60/0x60
[ 6870.644707] [<ffffffff8f01ae77>] ? ret_from_fork+0x57/0x70
[ 6870.650936] Code: 31 c0 31 d2 41 b9 20 00 08 02 b9 09 00 00 0
addrconf_dad_work is kicked to be scheduled when a device is brought
up. There is a race between addrcond_dad_work getting scheduled and
taking the rtnl lock and a process taking the link down (under rtnl).
The latter removes the host route from the inet6_addr as part of
addrconf_ifdown which is run for NETDEV_DOWN. The former attempts
to use the host route in __ipv6_ifa_notify. If the down event removes
the host route due to the race to the rtnl, then the BUG listed above
occurs.
Since the DAD sequence can not be aborted, add a check for the missing
host route in __ipv6_ifa_notify. The only way this should happen is due
to the previously mentioned race. The host route is created when the
address is added to an interface; it is only removed on a down event
where the address is kept. Add a warning if the host route is missing
AND the device is up; this is a situation that should never happen.
Fixes:
|
||
---|---|---|
.. | ||
ila | ||
netfilter | ||
addrconf.c | ||
addrconf_core.c | ||
addrlabel.c | ||
af_inet6.c | ||
ah6.c | ||
anycast.c | ||
calipso.c | ||
datagram.c | ||
esp6.c | ||
esp6_offload.c | ||
exthdrs.c | ||
exthdrs_core.c | ||
exthdrs_offload.c | ||
fib6_notifier.c | ||
fib6_rules.c | ||
fou6.c | ||
icmp.c | ||
inet6_connection_sock.c | ||
inet6_hashtables.c | ||
ip6_checksum.c | ||
ip6_fib.c | ||
ip6_flowlabel.c | ||
ip6_gre.c | ||
ip6_icmp.c | ||
ip6_input.c | ||
ip6_offload.c | ||
ip6_offload.h | ||
ip6_output.c | ||
ip6_tunnel.c | ||
ip6_udp_tunnel.c | ||
ip6_vti.c | ||
ip6mr.c | ||
ipcomp6.c | ||
ipv6_sockglue.c | ||
Kconfig | ||
Makefile | ||
mcast.c | ||
mcast_snoop.c | ||
mip6.c | ||
ndisc.c | ||
netfilter.c | ||
output_core.c | ||
ping.c | ||
proc.c | ||
protocol.c | ||
raw.c | ||
reassembly.c | ||
route.c | ||
seg6.c | ||
seg6_hmac.c | ||
seg6_iptunnel.c | ||
seg6_local.c | ||
sit.c | ||
syncookies.c | ||
sysctl_net_ipv6.c | ||
tcp_ipv6.c | ||
tcpv6_offload.c | ||
tunnel6.c | ||
udp.c | ||
udp_impl.h | ||
udp_offload.c | ||
udplite.c | ||
xfrm6_input.c | ||
xfrm6_output.c | ||
xfrm6_policy.c | ||
xfrm6_protocol.c | ||
xfrm6_state.c | ||
xfrm6_tunnel.c |