From: Florian Westphal Date: Thu, 19 Nov 2020 15:34:54 +0000 (+0100) Subject: netfilter: nf_tables: avoid false-postive lockdep splat X-Git-Tag: v5.10-rc7~20^2~24^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c0700dfa2cae44c033ed97dade8a2679c7d22a9d;p=thirdparty%2Fkernel%2Flinux.git netfilter: nf_tables: avoid false-postive lockdep splat 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 Link: https://lore.kernel.org/linux-kselftest/CA+G9fYvFUpODs+NkSYcnwKnXm62tmP=ksLeBPmB+KFrB2rvCtQ@mail.gmail.com/ Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 0f58e98542be2..23abf15785943 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 }