4.19-stable review patch. If anyone has any objections, please let me know.
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From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit 259eb32971e9eb24d1777a28d82730659f50fdcb ]
Module reference is bumped for each user, this should not ever happen.
But BUG_ON check should use rcu_access_pointer() instead.
If this ever happens, do WARN_ON_ONCE() instead of BUG_ON() and consolidate pointer check under the rcu read side lock section.
Fixes: fab4085f4e24 ("netfilter: log: nf_log_packet() as real unified interface") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_log.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c index a61d6df6e5f6..75bdeee325eb 100644 --- a/net/netfilter/nf_log.c +++ b/net/netfilter/nf_log.c @@ -202,11 +202,12 @@ void nf_logger_put(int pf, enum nf_log_type type) return; }
- BUG_ON(loggers[pf][type] == NULL); - rcu_read_lock(); logger = rcu_dereference(loggers[pf][type]); - module_put(logger->me); + if (!logger) + WARN_ON_ONCE(1); + else + module_put(logger->me); rcu_read_unlock(); } EXPORT_SYMBOL_GPL(nf_logger_put);