common: pick_addresses: fix bug with observer class that triggered #5205

The Observer class we defined to observe conf changes and thus avoid
triggering #5205 (as fixed by eb86eebe1ba42f04b46f7c3e3419b83eb6fe7f9a),
was returning always the same const static array, which would lead us to
always populate the observer's list with an observer for 'public_addr'.

This would of course become a problem when trying to obtain the observer
for 'cluster_add' during md_config_t::set_val() -- thus triggering the
same assert as initially reported on #5205.

Backport: cuttlefish
Fixes: #5205

Signed-off-by: Joao Eduardo Luis <jecluis@gmail.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/src/common/pick_address.cc b/src/common/pick_address.cc
index ff036c61360..f6853622ff9 100644
--- a/src/common/pick_address.cc
+++ b/src/common/pick_address.cc
@@ -50,15 +50,14 @@ static const struct sockaddr *find_ip_in_subnet_list(CephContext *cct,
 
 // observe this change
 struct Observer : public md_config_obs_t {
-  const char *conf_var;
-  Observer(const char *c) : conf_var(c) {}
+  const char *keys[2];
+  Observer(const char *c) {
+    keys[0] = c;
+    keys[1] = NULL;
+  }
 
   const char** get_tracked_conf_keys() const {
-    static const char *foo[] = {
-      conf_var,
-      NULL
-    };
-    return foo;
+    return (const char **)keys;
   }
   void handle_conf_change(const struct md_config_t *conf,
 			  const std::set <std::string> &changed) {