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-rw-r--r--security/selinux/avc.c19
1 files changed, 15 insertions, 4 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 1ed0f076aad..b4b5da1c0a4 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -868,8 +868,19 @@ u32 avc_policy_seqno(void)
void avc_disable(void)
{
- avc_flush();
- synchronize_rcu();
- if (avc_node_cachep)
- kmem_cache_destroy(avc_node_cachep);
+ /*
+ * If you are looking at this because you have realized that we are
+ * not destroying the avc_node_cachep it might be easy to fix, but
+ * I don't know the memory barrier semantics well enough to know. It's
+ * possible that some other task dereferenced security_ops when
+ * it still pointed to selinux operations. If that is the case it's
+ * possible that it is about to use the avc and is about to need the
+ * avc_node_cachep. I know I could wrap the security.c security_ops call
+ * in an rcu_lock, but seriously, it's not worth it. Instead I just flush
+ * the cache and get that memory back.
+ */
+ if (avc_node_cachep) {
+ avc_flush();
+ /* kmem_cache_destroy(avc_node_cachep); */
+ }
}