diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-04-13 11:13:33 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-04-15 14:28:50 -0700 |
| commit | 9cb7c013420f98fa6fd12fc6a5dc055170c108db (patch) | |
| tree | 29c97668ccf730991b009998580b80c67adc28cd /include/net | |
| parent | 268b41b34d9afd0e49bb266d5cca54c50abbe4c2 (diff) | |
ipv6: make ip6_rt_gc_expire an atomic_t
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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220413181333.649424-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/netns/ipv6.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h index 3d83b64471d3..b4af4837d80b 100644 --- a/include/net/netns/ipv6.h +++ b/include/net/netns/ipv6.h @@ -75,8 +75,8 @@ struct netns_ipv6 { struct list_head fib6_walkers; rwlock_t fib6_walker_lock; spinlock_t fib6_gc_lock; - unsigned int ip6_rt_gc_expire; - unsigned long ip6_rt_last_gc; + atomic_t ip6_rt_gc_expire; + unsigned long ip6_rt_last_gc; unsigned char flowlabel_has_excl; #ifdef CONFIG_IPV6_MULTIPLE_TABLES bool fib6_has_custom_rules; |