diff --git a/changelog.d/8817.bugfix b/changelog.d/8817.bugfix
new file mode 100644
index 0000000000000000000000000000000000000000..e45dbd2ba4f7fc9b9717a3d0f069e4ecb9b47197
--- /dev/null
+++ b/changelog.d/8817.bugfix
@@ -0,0 +1 @@
+Fix bug where logging could break after a call to SIGHUP.
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index 9c8dc785c667ebe811dbd982d4ab7da4159130b8..895b38ae761f8aff3f9305ea4a65054b0188d57b 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -32,6 +32,7 @@ from synapse.app.phone_stats_home import start_phone_stats_home
 from synapse.config.server import ListenerConfig
 from synapse.crypto import context_factory
 from synapse.logging.context import PreserveLoggingContext
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.util.async_helpers import Linearizer
 from synapse.util.daemonize import daemonize_process
 from synapse.util.rlimit import change_resource_limit
@@ -244,6 +245,7 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):
         # Set up the SIGHUP machinery.
         if hasattr(signal, "SIGHUP"):
 
+            @wrap_as_background_process("sighup")
             def handle_sighup(*args, **kwargs):
                 # Tell systemd our state, if we're using it. This will silently fail if
                 # we're not using systemd.
@@ -254,7 +256,13 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):
 
                 sdnotify(b"READY=1")
 
-            signal.signal(signal.SIGHUP, handle_sighup)
+            # We defer running the sighup handlers until next reactor tick. This
+            # 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)
+
+            signal.signal(signal.SIGHUP, run_sighup)
 
             register_sighup(refresh_certificate, hs)