From 80a992d7b953ea58dd45913d68855e396ad4d980 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Thu, 10 Dec 2020 16:56:05 +0000 Subject: [PATCH] Fix deadlock on SIGHUP (#8918) Fixes #8892 --- changelog.d/8918.bugfix | 1 + synapse/app/_base.py | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-) create mode 100644 changelog.d/8918.bugfix diff --git a/changelog.d/8918.bugfix b/changelog.d/8918.bugfix new file mode 100644 index 000000000..ae0f6745d --- /dev/null +++ b/changelog.d/8918.bugfix @@ -0,0 +1 @@ +Fix occasional deadlock when handling SIGHUP. diff --git a/synapse/app/_base.py b/synapse/app/_base.py index 895b38ae7..37ecdbe3d 100644 --- a/synapse/app/_base.py +++ b/synapse/app/_base.py @@ -245,6 +245,8 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]): # Set up the SIGHUP machinery. if hasattr(signal, "SIGHUP"): + reactor = hs.get_reactor() + @wrap_as_background_process("sighup") def handle_sighup(*args, **kwargs): # Tell systemd our state, if we're using it. This will silently fail if @@ -260,7 +262,9 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]): # is so that we're in a sane state, e.g. flushing the logs may fail # if the sighup happens in the middle of writing a log entry. def run_sighup(*args, **kwargs): - hs.get_clock().call_later(0, handle_sighup, *args, **kwargs) + # `callFromThread` should be "signal safe" as well as thread + # safe. + reactor.callFromThread(handle_sighup, *args, **kwargs) signal.signal(signal.SIGHUP, run_sighup)