From: Florian Westphal fw@strlen.de
commit c0700dfa2cae44c033ed97dade8a2679c7d22a9d upstream.
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=ksLe... Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/netfilter/nf_tables_api.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- 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 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 }