commit f069034ad1293841876f2ce8526643d39e80065a
author Barret Rhoden <brho@cs.berkeley.edu> Fri Jul 08 16:25:00 2016 -0400
committer Barret Rhoden <brho@cs.berkeley.edu> Fri Jul 08 16:25:00 2016 -0400
tree bf443033c6d28c1a805137d9b8e8265f17883e84
parent 9fd51b968e3f5ec10b7fd4f86b41903ff3b7fe3f

Fix refcnting bug in DTLS

I think this is right.  It's odd to up the refcnt on every set_dtls.  We're
just setting the value.  IIUC, the refcnt is meant to keep key alive since
we're storing a ref to it in V.

This bug was probably harmless - just some wasted memory.  You'd need 4
billion set_dtls calls followed by a poorly timed decref to cause serious
trouble.  =)

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>

user/parlib/dtls.c

diff --git a/user/parlib/dtls.c b/user/parlib/dtls.c
index afd8e28..4df4d54 100644
--- a/user/parlib/dtls.c
+++ b/user/parlib/dtls.c
@@ -170,11 +170,11 @@
 static inline void __set_dtls(dtls_data_t *dtls_data, dtls_key_t key, void *dtls)
 {
   assert(key);
-  __sync_fetch_and_add(&key->ref_count, 1);
 
   struct dtls_value *v = __get_dtls(dtls_data, key);
   if (!v) {
     v = __allocate_dtls_value(dtls_data, key);
+    __sync_fetch_and_add(&key->ref_count, 1);
     v->key = key;
     TAILQ_INSERT_HEAD(&dtls_data->list, v, link);
   }