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netfilter: nf_tables: fix false-positive lockdep splat

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[ Upstream commit b9f052dc68 ]

->abort invocation may cause splat on debug kernels:

WARNING: suspicious RCU usage
net/netfilter/nft_set_pipapo.c:1697 suspicious rcu_dereference_check() usage!
[..]
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by nft/133554: [..] (nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid
[..]
 lockdep_rcu_suspicious+0x1ad/0x260
 nft_pipapo_abort+0x145/0x180
 __nf_tables_abort+0x5359/0x63d0
 nf_tables_abort+0x24/0x40
 nfnetlink_rcv+0x1a0a/0x22c0
 netlink_unicast+0x73c/0x900
 netlink_sendmsg+0x7f0/0xc20
 ____sys_sendmsg+0x48d/0x760

Transaction mutex is held, so parallel updates are not possible.
Switch to _protected and check mutex is held for lockdep enabled builds.

Fixes: 212ed75dc5 ("netfilter: nf_tables: integrate pipapo into commit protocol")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Florian Westphal 2023-08-08 20:40:17 +02:00 committed by Greg Kroah-Hartman
parent b2f6d73395
commit 82109740d6
1 changed files with 12 additions and 1 deletions
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13
net/netfilter/nft_set_pipapo.c
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@ -1665,6 +1665,17 @@ static void nft_pipapo_commit(const struct nft_set *set)
priv->clone = new_clone;
}
static bool nft_pipapo_transaction_mutex_held(const struct nft_set *set)
{
#ifdef CONFIG_PROVE_LOCKING
const struct net *net = read_pnet(&set->net);
return lockdep_is_held(&nft_pernet(net)->commit_mutex);
#else
return true;
#endif
}
static void nft_pipapo_abort(const struct nft_set *set)
{
struct nft_pipapo *priv = nft_set_priv(set);
@ -1673,7 +1684,7 @@ static void nft_pipapo_abort(const struct nft_set *set)
if (!priv->dirty)
return;
m = rcu_dereference(priv->match);
m = rcu_dereference_protected(priv->match, nft_pipapo_transaction_mutex_held(set));
new_clone = pipapo_clone(m);
if (IS_ERR(new_clone))