[PATCH 1/3] sunrpc: check that domain table is empty at module unload.

[NeilBrown <neilb@suse.de>]

The domain table should be empty at module unload.  If it isn't there is
a bug somewhere.  So check and report.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
---
 net/sunrpc/sunrpc.h      |    1 +
 net/sunrpc/sunrpc_syms.c |    2 ++
 net/sunrpc/svcauth.c     |   18 ++++++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/net/sunrpc/sunrpc.h b/net/sunrpc/sunrpc.h
index 47a756503d11..f6fe2e6cd65a 100644
--- a/net/sunrpc/sunrpc.h
+++ b/net/sunrpc/sunrpc.h
@@ -52,4 +52,5 @@ static inline int sock_is_loopback(struct sock *sk)
 
 int rpc_clients_notifier_register(void);
 void rpc_clients_notifier_unregister(void);
+void auth_domain_cleanup(void);
 #endif /* _NET_SUNRPC_SUNRPC_H */
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index f9edaa9174a4..236fadc4a439 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -23,6 +23,7 @@
 #include <linux/sunrpc/rpc_pipe_fs.h>
 #include <linux/sunrpc/xprtsock.h>
 
+#include "sunrpc.h"
 #include "netns.h"
 
 unsigned int sunrpc_net_id;
@@ -131,6 +132,7 @@ cleanup_sunrpc(void)
 	unregister_rpc_pipefs();
 	rpc_destroy_mempool();
 	unregister_pernet_subsys(&sunrpc_net_ops);
+	auth_domain_cleanup();
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	rpc_unregister_sysctl();
 #endif
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index 552617e3467b..477890e8b9d8 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -205,3 +205,21 @@ struct auth_domain *auth_domain_find(char *name)
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(auth_domain_find);
+
+void auth_domain_cleanup(void)
+{
+	/* There should be no auth_domains left at module unload */
+	int h;
+	bool found = false;
+
+	for (h = 0; h < DN_HASHMAX; h++) {
+		struct auth_domain *hp;
+
+		hlist_for_each_entry(hp, auth_domain_table+h, hash) {
+			found = true;
+			printk(KERN_WARNING "sunrpc: domain %s still present at module unload.\n",
+			       hp->name);
+		}
+	}
+	WARN(found, "sunrpc: auth_domain_table not clean -> memory leak\n");
+}