From: Qian Cai cai@lca.pw
[ Upstream commit 0a6a9515fe390976cd762c52d8d4f446d7a14285 ]
It is safe to traverse &net->nft.tables with &net->nft.commit_mutex held using list_for_each_entry_rcu(). Silence the PROVE_RCU_LIST false positive,
WARNING: suspicious RCU usage net/netfilter/nf_tables_api.c:523 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1 1 lock held by iptables/1384: #0: ffffffff9745c4a8 (&net->nft.commit_mutex){+.+.}, at: nf_tables_valid_genid+0x25/0x60 [nf_tables]
Call Trace: dump_stack+0xa1/0xea lockdep_rcu_suspicious+0x103/0x10d nft_table_lookup.part.0+0x116/0x120 [nf_tables] nf_tables_newtable+0x12c/0x7d0 [nf_tables] nfnetlink_rcv_batch+0x559/0x1190 [nfnetlink] nfnetlink_rcv+0x1da/0x210 [nfnetlink] netlink_unicast+0x306/0x460 netlink_sendmsg+0x44b/0x770 ____sys_sendmsg+0x46b/0x4a0 ___sys_sendmsg+0x138/0x1a0 __sys_sendmsg+0xb6/0x130 __x64_sys_sendmsg+0x48/0x50 do_syscall_64+0x69/0xf4 entry_SYSCALL_64_after_hwframe+0x49/0xb3
Signed-off-by: Qian Cai cai@lca.pw Acked-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_api.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 11a2a7b5312ee..61c544801e534 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -520,7 +520,8 @@ static struct nft_table *nft_table_lookup(const struct net *net, if (nla == NULL) return ERR_PTR(-EINVAL);
- list_for_each_entry_rcu(table, &net->nft.tables, list) { + list_for_each_entry_rcu(table, &net->nft.tables, list, + lockdep_is_held(&net->nft.commit_mutex)) { if (!nla_strcmp(nla, table->name) && table->family == family && nft_active_genmask(table, genmask))