disconnect: separate connections and easy handles better

Do not assume/store assocation between a given easy handle and the
connection if it can be avoided.

Long-term, the 'conn->data' pointer should probably be removed as it is a
little too error-prone. Still used very widely though.

Reported-by: masbug on github
Fixes #3391
Closes #3400

1 files changed, 2 insertions, 7 deletions

diff --git a/lib/url.c b/lib/url.c
index 5cd286650..2ec45873f 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -769,7 +769,6 @@ CURLcode Curl_disconnect(struct Curl_easy *data,
     return CURLE_OK;
   }
 
-  conn->data = data;
   if(conn->dns_entry != NULL) {
     Curl_resolv_unlock(data, conn->dns_entry);
     conn->dns_entry = NULL;
@@ -788,14 +787,13 @@ CURLcode Curl_disconnect(struct Curl_easy *data,
 
     /* unlink ourselves! */
   infof(data, "Closing connection %ld\n", conn->connection_id);
-  Curl_conncache_remove_conn(conn, TRUE);
+  Curl_conncache_remove_conn(data, conn, TRUE);
 
   free_idnconverted_hostname(&conn->host);
   free_idnconverted_hostname(&conn->conn_to_host);
   free_idnconverted_hostname(&conn->http_proxy.host);
   free_idnconverted_hostname(&conn->socks_proxy.host);
 
-  DEBUGASSERT(conn->data == data);
   /* this assumes that the pointer is still there after the connection was
      detected from the cache */
   Curl_ssl_close(conn, FIRSTSOCKET);
@@ -960,8 +958,6 @@ static bool extract_if_dead(struct connectdata *conn,
        handles in pipeline and the connection isn't already marked in
        use */
     bool dead;
-
-    conn->data = data;
     if(conn->handler->connection_check) {
       /* The protocol has a special method for checking the state of the
          connection. Use it to check if the connection is dead. */
@@ -977,8 +973,7 @@ static bool extract_if_dead(struct connectdata *conn,
 
     if(dead) {
       infof(data, "Connection %ld seems to be dead!\n", conn->connection_id);
-      Curl_conncache_remove_conn(conn, FALSE);
-      conn->data = NULL; /* detach */
+      Curl_conncache_remove_conn(data, conn, FALSE);
       return TRUE;
     }
   }