From dcca56babad3a42ac9967995f7e6f9db51e37353 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Fri, 19 Jul 2019 17:57:00 +0100 Subject: [PATCH] Add a delay to key lookup lock release to fix stack overflow A tactical call_later here should fix #5723 --- synapse/crypto/keyring.py | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index efa72dc5f..e8bb420ad 100644 --- a/synapse/crypto/keyring.py +++ b/synapse/crypto/keyring.py @@ -259,6 +259,10 @@ class Keyring(object): # When we've finished fetching all the keys for a given server_name, # drop the lock by resolving the deferred in key_downloads. + def drop_server_lock(server_name): + d = self.key_downloads.pop(server_name) + d.callback(None) + def lookup_done(res, verify_request): server_name = verify_request.server_name server_requests = server_to_request_ids[server_name] @@ -269,8 +273,10 @@ class Keyring(object): with PreserveLoggingContext(ctx): logger.debug("Releasing key lookup lock on %s", server_name) - d = self.key_downloads.pop(server_name) - d.callback(None) + # ... but not immediately, as that can cause stack explosions if + # we get a long queue of lookups. + self.clock.call_later(0, drop_server_lock, server_name) + return res for verify_request in verify_requests: