netfilter: nf_log: don't zap all loggers on unregister

like nf_log_unset, nf_log_unregister must not reset the list of loggers.
Otherwise, a call to nf_log_unregister() will render loggers of other nf
protocols unusable:

iptables -A INPUT -j LOG
modprobe nf_log_arp ; rmmod nf_log_arp
iptables -A INPUT -j LOG
iptables: No chain/target/match by that name

Fixes: 30e0c6a6be ("netfilter: nf_log: prepare net namespace support for loggers")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index 675d12c..a5ebd7d 100644 (file)
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -107,11 +107,15 @@ EXPORT_SYMBOL(nf_log_register);
 
 void nf_log_unregister(struct nf_logger *logger)
 {
+       const struct nf_logger *log;
        int i;
 
        mutex_lock(&nf_log_mutex);
-       for (i = 0; i < NFPROTO_NUMPROTO; i++)
-               RCU_INIT_POINTER(loggers[i][logger->type], NULL);
+       for (i = 0; i < NFPROTO_NUMPROTO; i++) {
+               log = nft_log_dereference(loggers[i][logger->type]);
+               if (log == logger)
+                       RCU_INIT_POINTER(loggers[i][logger->type], NULL);
+       }
        mutex_unlock(&nf_log_mutex);
 }
 EXPORT_SYMBOL(nf_log_unregister);