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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2008-04-21 18:12:33 -0700
committerJames Morris <jmorris@namei.org>2008-04-22 15:37:23 +1000
commit618442509128fe4514be94de70ce54075cd9a706 (patch)
tree9aea814978791abd8c4f9a5c60de879b2811c063 /security/selinux/avc.c
parent0f5e64200f20fc8f5b759c4010082f577ab0af3f (diff)
SELinux fixups needed for preemptable RCU from -rt
The attached patch needs to move from -rt to mainline given preemptable RCU. This patch fixes SELinux code that implicitly assumes that disabling preemption prevents an RCU grace period from completing, an assumption that is valid for Classic RCU, but not necessarily for preemptable RCU. Explicit rcu_read_lock() calls are thus added. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/selinux/avc.c')
-rw-r--r--security/selinux/avc.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 1d69f6649bff..95a8ef4a5073 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -312,6 +312,7 @@ static inline int avc_reclaim_node(void)
if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
continue;
+ rcu_read_lock();
list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
if (atomic_dec_and_test(&node->ae.used)) {
/* Recently Unused */
@@ -319,11 +320,13 @@ static inline int avc_reclaim_node(void)
avc_cache_stats_incr(reclaims);
ecx++;
if (ecx >= AVC_CACHE_RECLAIM) {
+ rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
goto out;
}
}
}
+ rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
}
out:
@@ -821,8 +824,14 @@ int avc_ss_reset(u32 seqno)
for (i = 0; i < AVC_CACHE_SLOTS; i++) {
spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
+ /*
+ * With preemptable RCU, the outer spinlock does not
+ * prevent RCU grace periods from ending.
+ */
+ rcu_read_lock();
list_for_each_entry(node, &avc_cache.slots[i], list)
avc_node_delete(node);
+ rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
}