From 1d001b0a6182b0d2f41a8d687f7522b6f1e94280 Mon Sep 17 00:00:00 2001 From: Jiayuan Chen Date: Wed, 20 May 2026 10:34:09 +0800 Subject: [PATCH] netfilter: nft_fib_ipv6: walk fib6_siblings under RCU nft_fib6_info_nh_uses_dev() runs from nft_fib6_eval() in softirq under rcu_read_lock(). fib6_siblings is modified by writers that hold tb6_lock but do not wait for RCU readers, so the sibling walk should use list_for_each_entry_rcu(): it adds READ_ONCE() on the ->next pointer and lets CONFIG_PROVE_RCU_LIST validate the locking. No functional change for non-debug builds. Fixes: 1c32b24c234b ("netfilter: nft_fib_ipv6: switch to fib6_lookup") Signed-off-by: Jiayuan Chen Signed-off-by: Florian Westphal --- net/ipv6/netfilter/nft_fib_ipv6.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c index 8b2dba88ee96..5e192a446ec8 100644 --- a/net/ipv6/netfilter/nft_fib_ipv6.c +++ b/net/ipv6/netfilter/nft_fib_ipv6.c @@ -170,7 +170,7 @@ static bool nft_fib6_info_nh_uses_dev(struct fib6_info *rt, if (nft_fib6_info_nh_dev_match(nh_dev, dev)) return true; - list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings) { + list_for_each_entry_rcu(iter, &rt->fib6_siblings, fib6_siblings) { nh_dev = fib6_info_nh_dev(iter); if (nft_fib6_info_nh_dev_match(nh_dev, dev))