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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 14/28] netfilter: nf_tables: silence a RCU-list warning in nft_table_lookup()
Date: Mon, 30 Mar 2020 21:21:22 +0200	[thread overview]
Message-ID: <20200330192136.230459-15-pablo@netfilter.org> (raw)
In-Reply-To: <20200330192136.230459-1-pablo@netfilter.org>

From: Qian Cai <cai@lca.pw>

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>
---
 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 ace325218edb..c1e04ac21392 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))
-- 
2.11.0


  parent reply	other threads:[~2020-03-30 19:22 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-30 19:21 [PATCH 00/28] Netfilter/IPVS updates for net-next Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 01/28] netfilter: nf_tables: move nft_expr_clone() to nf_tables_api.c Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 02/28] netfilter: nf_tables: pass context to nft_set_destroy() Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 03/28] netfilter: nf_tables: allow to specify stateful expression in set definition Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 04/28] netfilter: nf_tables: fix double-free on set expression from the error path Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 05/28] netfilter: nf_tables: add nft_set_elem_expr_destroy() and use it Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 06/28] netfilter: flowtable: fix NULL pointer dereference in tunnel offload support Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 07/28] netfilter: ctnetlink: Add missing annotation for ctnetlink_parse_nat_setup() Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 08/28] netfilter: conntrack: Add missing annotations for nf_conntrack_all_lock() and nf_conntrack_all_unlock() Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 09/28] ipvs: optimize tunnel dumps for icmp errors Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 10/28] netfilter: conntrack: export nf_ct_acct_update() Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 11/28] netfilter: nf_tables: add enum nft_flowtable_flags to uapi Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 12/28] netfilter: flowtable: add counter support Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 13/28] netfilter: flowtable: Fix incorrect tc_setup_type type Pablo Neira Ayuso
2020-03-30 19:21 ` Pablo Neira Ayuso [this message]
2020-03-30 19:21 ` [PATCH 15/28] netfilter: flowtable: Use rw sem as flow block lock Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 16/28] netfilter: flowtable: Use work entry per offload command Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 17/28] netfilter: nf_queue: make nf_queue_entry_release_refs static Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 18/28] netfilter: nf_queue: place bridge physports into queue_entry struct Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 19/28] netfilter: nf_queue: do not release refcouts until nf_reinject is done Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 20/28] netfilter: nf_queue: prefer nf_queue_entry_free Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 21/28] netfilter: ctnetlink: be more strict when NF_CONNTRACK_MARK is not set Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 22/28] netfilter: nft_set_bitmap: initialize set element extension in lookups Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 23/28] netfilter: nft_dynset: validate set expression definition Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 24/28] netfilter: nf_tables: skip set types that do not support for expressions Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 25/28] netfilter: conntrack: add nf_ct_acct_add() Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 26/28] netfilter: flowtable: add counter support in HW offload Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 27/28] netfilter: nft_exthdr: fix endianness of tcp option cast Pablo Neira Ayuso
2020-03-30 19:21 ` [PATCH 28/28] ipvs: fix uninitialized variable warning Pablo Neira Ayuso
2020-03-31  3:11 ` [PATCH 00/28] Netfilter/IPVS updates for net-next David Miller

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