security: Apply lockdep-based checking to rcu_dereference() uses

Apply lockdep-ified RCU primitives to key_gc_keyring() and
keyring_destroy().

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-12-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/security/keys/gc.c b/security/keys/gc.c
index 4770be3..1990231 100644 (file)
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -77,7 +77,8 @@ static bool key_gc_keyring(struct key *keyring, time_t limit)
                goto dont_gc;
 
        /* scan the keyring looking for dead keys */
-       klist = rcu_dereference(keyring->payload.subscriptions);
+       klist = rcu_dereference_check(keyring->payload.subscriptions,
+                                     lockdep_is_held(&key_serial_lock));
        if (!klist)
                goto dont_gc;
 

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 8ec0274..e814d21 100644 (file)
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -151,7 +151,9 @@ static void keyring_destroy(struct key *keyring)
                write_unlock(&keyring_name_lock);
        }
 
-       klist = rcu_dereference(keyring->payload.subscriptions);
+       klist = rcu_dereference_check(keyring->payload.subscriptions,
+                                     rcu_read_lock_held() ||
+                                     atomic_read(&keyring->usage) == 0);
        if (klist) {
                for (loop = klist->nkeys - 1; loop >= 0; loop--)
                        key_put(klist->keys[loop]);