[PATCH tip/core/rcu 12/21] security: apply lockdep-based checking to rcu_dereference() uses

From: Paul E. McKenney
Date: Mon Feb 22 2010 - 20:05:55 EST


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

Cc: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
security/keys/gc.c | 3 ++-
security/keys/keyring.c | 4 +++-
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/security/keys/gc.c b/security/keys/gc.c
index 4770be3..1990231 100644
--- 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
--- 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]);
--
1.6.6

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