From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org
Subject: [PATCH net 4/4] netfilter: nf_tables: avoid false-postive lockdep splat
Date: Sat, 21 Nov 2020 13:36:01 +0100 [thread overview]
Message-ID: <20201121123601.21733-5-pablo@netfilter.org> (raw)
In-Reply-To: <20201121123601.21733-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
There are reports wrt lockdep splat in nftables, e.g.:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 31416 at net/netfilter/nf_tables_api.c:622
lockdep_nfnl_nft_mutex_not_held+0x28/0x38 [nf_tables]
...
These are caused by an earlier, unrelated bug such as a n ABBA deadlock
in a different subsystem.
In such an event, lockdep is disabled and lockdep_is_held returns true
unconditionally. This then causes the WARN() in nf_tables.
Make the WARN conditional on lockdep still active to avoid this.
Fixes: f102d66b335a417 ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/linux-kselftest/CA+G9fYvFUpODs+NkSYcnwKnXm62tmP=ksLeBPmB+KFrB2rvCtQ@mail.gmail.com/
Signed-off-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 0f58e98542be..23abf1578594 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -619,7 +619,8 @@ static int nft_request_module(struct net *net, const char *fmt, ...)
static void lockdep_nfnl_nft_mutex_not_held(void)
{
#ifdef CONFIG_PROVE_LOCKING
- WARN_ON_ONCE(lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
+ if (debug_locks)
+ WARN_ON_ONCE(lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
#endif
}
--
2.20.1
prev parent reply other threads:[~2020-11-21 12:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-21 12:35 [PATCH net 0/4] Netfilter fixes for net Pablo Neira Ayuso
2020-11-21 12:35 ` [PATCH net 1/4] netfilter: nftables_offload: set address type in control dissector Pablo Neira Ayuso
2020-11-22 0:44 ` Jakub Kicinski
2020-11-22 10:49 ` Pablo Neira Ayuso
2020-11-21 12:35 ` [PATCH net 2/4] netfilter: nftables_offload: build mask based from the matching bytes Pablo Neira Ayuso
2020-11-21 12:36 ` [PATCH net 3/4] netfilter: ipset: prevent uninit-value in hash_ip6_add Pablo Neira Ayuso
2020-11-21 12:36 ` Pablo Neira Ayuso [this message]
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