9cb7c01342
Reads and Writes to ip6_rt_gc_expire always have been racy,
as syzbot reported lately [1]
There is a possible risk of under-flow, leading
to unexpected high value passed to fib6_run_gc(),
although I have not observed this in the field.
Hosts hitting ip6_dst_gc() very hard are under pretty bad
state anyway.
[1]
BUG: KCSAN: data-race in ip6_dst_gc / ip6_dst_gc
read-write to 0xffff888102110744 of 4 bytes by task 13165 on cpu 1:
ip6_dst_gc+0x1f3/0x220 net/ipv6/route.c:3311
dst_alloc+0x9b/0x160 net/core/dst.c:86
ip6_dst_alloc net/ipv6/route.c:344 [inline]
icmp6_dst_alloc+0xb2/0x360 net/ipv6/route.c:3261
mld_sendpack+0x2b9/0x580 net/ipv6/mcast.c:1807
mld_send_cr net/ipv6/mcast.c:2119 [inline]
mld_ifc_work+0x576/0x800 net/ipv6/mcast.c:2651
process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
worker_thread+0x618/0xa70 kernel/workqueue.c:2436
kthread+0x1a9/0x1e0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30
read-write to 0xffff888102110744 of 4 bytes by task 11607 on cpu 0:
ip6_dst_gc+0x1f3/0x220 net/ipv6/route.c:3311
dst_alloc+0x9b/0x160 net/core/dst.c:86
ip6_dst_alloc net/ipv6/route.c:344 [inline]
icmp6_dst_alloc+0xb2/0x360 net/ipv6/route.c:3261
mld_sendpack+0x2b9/0x580 net/ipv6/mcast.c:1807
mld_send_cr net/ipv6/mcast.c:2119 [inline]
mld_ifc_work+0x576/0x800 net/ipv6/mcast.c:2651
process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
worker_thread+0x618/0xa70 kernel/workqueue.c:2436
kthread+0x1a9/0x1e0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30
value changed: 0x00000bb3 -> 0x00000ba9
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11607 Comm: kworker/0:21 Not tainted 5.18.0-rc1-syzkaller-00037-g42e7a03d3bad-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: mld mld_ifc_work
Fixes:
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.. | ||
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 | ||
ioam6.c | ||
ioam6_iptunnel.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 | ||
rpl.c | ||
rpl_iptunnel.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 |