diff options
| author | Jiayuan Chen <jiayuan.chen@linux.dev> | 2026-05-27 13:31:30 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-29 12:40:05 -0700 |
| commit | 9f72412bcf60144f252b0d6205106abf14344abc (patch) | |
| tree | 26562abafb4ba54a411c99602262599da37caafc | |
| parent | f72eed9b84fb771019a955908132410a9ba9ea3f (diff) | |
ipv6: fix possible infinite loop in rt6_fill_node()
Sashiko reported this issue [1]. Apply the same fix as
commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()").
Writers holding tb6_lock can list_del_rcu(&rt->fib6_siblings)
without waiting for RCU readers; rt->fib6_siblings.next then still
points into the old ring and this softirq-side walker never reaches
&rt->fib6_siblings, causing a CPU stall. fib6_del_route() always
WRITE_ONCE()s rt->fib6_nsiblings to 0 before list_del_rcu(), so an
inside-loop check is a reliable detach signal.
[1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev
Fixes: d9ccb18f83ea ("ipv6: Fix soft lockups in fib6_select_path under high next hop churn")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260527053133.180695-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv6/route.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index b106e5fef9cb..dad416fdc585 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5902,6 +5902,8 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, goto nla_put_failure; } + if (!READ_ONCE(rt->fib6_nsiblings)) + break; } rcu_read_unlock(); |