Merge commit '43726783e' into dinsic

* commit '43726783e': (22 commits)
  1.17.0rc1
  Fix some spelling mistakes / typos. (#7811)
  `update_membership` declaration: now always returns an event id. (#7809)
  Improve stacktraces from exceptions in background processes (#7808)
  Fix `can only concatenate list (not "tuple") to list` exception (#7810)
  Pass original request headers from workers to the main process. (#7797)
  Generate real events when we reject invites (#7804)
  Add `HomeServer.signing_key` property (#7805)
  Revert "Update the installation docs on apt-transport-https (#7801)"
  Do not use simplejson in Synapse. (#7800)
  Stop passing bytes when dumping JSON (#7799)
  Update the installation docs on apt-transport-https (#7801)
  shuffle changelog slightly
  Change Caddy links (old is deprecated) (#7789)
  Stop populating unused table `local_invites`. (#7793)
  Refactor getting replication updates from database v2. (#7740)
  Add libwebp dependency to Dockerfile (#7791)
  Add documentation for JWT login type and improve sample config. (#7776)
  Convert the appservice handler to async/await. (#7775)
  Don't ignore `set_tweak` actions with no explicit `value`. (#7766)
  ...

1 files changed, 9 insertions, 1 deletions

diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py

index 13785038ad..a9269196b3 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -22,6 +22,7 @@ from typing import TYPE_CHECKING, Dict, Optional, Set
 from prometheus_client.core import REGISTRY, Counter, Gauge
 
 from twisted.internet import defer
+from twisted.python.failure import Failure
 
 from synapse.logging.context import LoggingContext, PreserveLoggingContext
 
@@ -212,7 +213,14 @@ def run_as_background_process(desc, func, *args, **kwargs):
 
                 return (yield result)
             except Exception:
-                logger.exception("Background process '%s' threw an exception", desc)
+                # failure.Failure() fishes the original Failure out of our stack, and
+                # thus gives us a sensible stack trace.
+                f = Failure()
+                logger.error(
+                    "Background process '%s' threw an exception",
+                    desc,
+                    exc_info=(f.type, f.value, f.getTracebackObject()),
+                )
             finally:
                 _background_process_in_flight_count.labels(desc).dec()