1 files changed, 5 insertions, 1 deletions
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index 4b2a16a6a9..650e44de22 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -453,7 +453,11 @@ class Linearizer:
         #
         # This needs to happen while we hold the lock. We could put it on the
         # exit path, but that would slow down the uncontended case.
-        await self._clock.sleep(0)
+        try:
+            await self._clock.sleep(0)
+        except CancelledError:
+            self._release_lock(key, entry)
+            raise
 
         return entry