path: root/security
diff options
authorDavid Howells <dhowells@redhat.com>2010-04-27 14:05:11 -0700
committerJames Morris <jmorris@namei.org>2010-04-28 08:37:15 +1000
commitb59ec78cdcc57e02bc3dddfa7134a2f0fd15c34d (patch)
tree60ba3c907d4d83873bce5eb645ae8bd9415399b8 /security
parentb91ce4d14a21fc04d165be30319541e0f9204f15 (diff)
keys: don't need to use RCU in keyring_read() as semaphore is held
keyring_read() doesn't need to use rcu_dereference() to access the keyring payload as the caller holds the key semaphore to prevent modifications from happening whilst the data is read out. This should solve the following warning: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- security/keys/keyring.c:204 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by keyctl/2144: #0: (&key->sem){+++++.}, at: [<ffffffff81177f7c>] keyctl_read_key+0x9c/0xcf stack backtrace: Pid: 2144, comm: keyctl Not tainted 2.6.34-rc2-cachefs #113 Call Trace: [<ffffffff8105121f>] lockdep_rcu_dereference+0xaa/0xb2 [<ffffffff811762d5>] keyring_read+0x4d/0xe7 [<ffffffff81177f8c>] keyctl_read_key+0xac/0xcf [<ffffffff811788d4>] sys_keyctl+0x75/0xb9 [<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells <dhowells@redhat.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
1 files changed, 1 insertions, 1 deletions
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index e814d2109f8..dd7cd0f8e13 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -201,7 +201,7 @@ static long keyring_read(const struct key *keyring,
int loop, ret;
ret = 0;
- klist = rcu_dereference(keyring->payload.subscriptions);
+ klist = keyring->payload.subscriptions;
if (klist) {
/* calculate how much data we could return */