Merge pull request #2918 from JorisOnGithub/bugfix/fix-gthread-deadlock

gthread: only read sockets when they are readable (#2917)

gunicorn/workers/gthread.py

@@ -40,12 +40,15 @@ def __init__(self, cfg, sock, client, server):
 
         self.timeout = None
         self.parser = None
+        self.initialized = False
 
         # set the socket to non blocking
         self.sock.setblocking(False)
 
     def init(self):
+        self.initialized = True
         self.sock.setblocking(True)
+
         if self.parser is None:
             # wrap the socket if needed
             if self.cfg.is_ssl:
@@ -120,23 +123,28 @@ def accept(self, server, listener):
             # initialize the connection object
             conn = TConn(self.cfg, sock, client, server)
             self.nr_conns += 1
-            # enqueue the job
-            self.enqueue_req(conn)
+
+            # wait until socket is readable
+            with self._lock:
+                self.poller.register(conn.sock, selectors.EVENT_READ,
+                                     partial(self.on_client_socket_readable, conn))
         except EnvironmentError as e:
             if e.errno not in (errno.EAGAIN, errno.ECONNABORTED,
                                errno.EWOULDBLOCK):
                 raise
 
-    def reuse_connection(self, conn, client):
+    def on_client_socket_readable(self, conn, client):
         with self._lock:
             # unregister the client from the poller
             self.poller.unregister(client)
-            # remove the connection from keepalive
-            try:
-                self._keep.remove(conn)
-            except ValueError:
-                # race condition
-                return
+
+            if conn.initialized:
+                # remove the connection from keepalive
+                try:
+                    self._keep.remove(conn)
+                except ValueError:
+                    # race condition
+                    return
 
         # submit the connection to a worker
         self.enqueue_req(conn)
@@ -249,7 +257,7 @@ def finish_request(self, fs):
 
                     # add the socket to the event loop
                     self.poller.register(conn.sock, selectors.EVENT_READ,
-                                         partial(self.reuse_connection, conn))
+                                         partial(self.on_client_socket_readable, conn))
             else:
                 self.nr_conns -= 1
                 conn.close()