Description

Today, when a filesystem watch callback returns a non-OK status or throws an exception, the error gets propagated to FileEventImpl which uses THROW_IF_NOT_OK.

Since there's no exception handler in the libevent loop, this causes std::terminate to be called, which crashes Envoy.

Stack Trace:

Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.119][234999][warning][misc] [source/common/protobuf/message_validator_impl.cc:23] Deprecated field: type envoy.config.core.v3.HeaderValueOption Using deprecated option 'envoy.config.core.v3.HeaderValueOption.append' from file base.proto. This configuration will be removed from Envoy soon. Please see https://www.envoyproxy.io/docs/envoy/latest/version_history/version_history for details. If continued use of this field is absolutely necessary, see https://www.envoyproxy.io/docs/envoy/latest/configuration/operations/runtime#using-runtime-overrides-for-deprecated-features for how to apply a temporary and highly discouraged override.
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.120][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '0_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.123][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '1_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.126][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '2_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.127][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '3_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.128][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '4_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.130][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '5_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.132][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener '6_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.134][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener 'mtls_untrusted_regional_transparent_tunnel_listener'
Dec 11 00:11:26 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:26.135][234999][info][upstream] [source/common/listener_manager/lds_api.cc:109] lds: add/update listener 'mtls_app_trusted_regional_transparent_tunnel_listener'
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.097][234999][critical][main] [source/exe/terminate_handler.cc:36] std::terminate called! Uncaught unknown exception, see trace.
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.097][234999][critical][backtrace] [./source/server/backtrace.h:113] Backtrace (use tools/stack_decode.py to get line numbers):
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.097][234999][critical][backtrace] [./source/server/backtrace.h:114] Envoy version: 5eaabe0bbaad4612cb85473cd151039d8f1a2760/1.34.2-dev/Clean/RELEASE/BoringSSL
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.097][234999][critical][backtrace] [./source/server/backtrace.h:116] Address mapping: 558d8afcc000-558d8ee2f000 /usr/local/bin/envoy
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.100][234999][critical][backtrace] [./source/server/backtrace.h:123] #0: [0x558d8da5784f]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.102][234999][critical][backtrace] [./source/server/backtrace.h:123] #1: [0x558d8edd8673]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.104][234999][critical][backtrace] [./source/server/backtrace.h:123] #2: [0x558d8e3b120b]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.106][234999][critical][backtrace] [./source/server/backtrace.h:121] #3: Envoy::Filesystem::WatcherImpl::onInotifyEvent() [0x558d8e3990c3]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.108][234999][critical][backtrace] [./source/server/backtrace.h:123] #4: [0x558d8e3998d2]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.109][234999][critical][backtrace] [./source/server/backtrace.h:123] #5: [0x558d8e393de6]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.111][234999][critical][backtrace] [./source/server/backtrace.h:121] #6: Envoy::Event::FileEventImpl::mergeInjectedEventsAndRunCb() [0x558d8e394eb5]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.113][234999][critical][backtrace] [./source/server/backtrace.h:123] #7: [0x558d8e710823]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.115][234999][critical][backtrace] [./source/server/backtrace.h:121] #8: event_base_loop [0x558d8e70d4a1]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.117][234999][critical][backtrace] [./source/server/backtrace.h:121] #9: Envoy::Server::InstanceBase::run() [0x558d8daa2b99]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.119][234999][critical][backtrace] [./source/server/backtrace.h:121] #10: Envoy::MainCommonBase::run() [0x558d8da4327a]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.121][234999][critical][backtrace] [./source/server/backtrace.h:121] #11: Envoy::MainCommon::main() [0x558d8da44234]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.123][234999][critical][backtrace] [./source/server/backtrace.h:121] #12: main [0x558d8afcc11c]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.123][234999][critical][backtrace] [./source/server/backtrace.h:123] #13: [0x7f1d54073efb]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.123][234999][critical][backtrace] [./source/server/backtrace.h:121] #14: __libc_start_main [0x7f1d54073fbb]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:121] #15: _start [0x558d8afcc02e]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:129] Caught Aborted, suspect faulting address 0x395f7
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:113] Backtrace (use tools/stack_decode.py to get line numbers):
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:114] Envoy version: 5eaabe0bbaad4612cb85473cd151039d8f1a2760/1.34.2-dev/Clean/RELEASE/BoringSSL
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:116] Address mapping: 558d8afcc000-558d8ee2f000 /usr/local/bin/envoy
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:123] #0: [0x7f1d54089c90]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:121] #1: gsignal [0x7f1d54089bde]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.124][234999][critical][backtrace] [./source/server/backtrace.h:121] #2: abort [0x7f1d54072832]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.126][234999][critical][backtrace] [./source/server/backtrace.h:123] #3: [0x558d8da5785c]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.128][234999][critical][backtrace] [./source/server/backtrace.h:123] #4: [0x558d8edd8673]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.129][234999][critical][backtrace] [./source/server/backtrace.h:123] #5: [0x558d8e3b120b]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.129][234999][critical][backtrace] [./source/server/backtrace.h:121] #6: Envoy::Filesystem::WatcherImpl::onInotifyEvent() [0x558d8e3990c3]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.131][234999][critical][backtrace] [./source/server/backtrace.h:123] #7: [0x558d8e3998d2]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.133][234999][critical][backtrace] [./source/server/backtrace.h:123] #8: [0x558d8e393de6]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.133][234999][critical][backtrace] [./source/server/backtrace.h:121] #9: Envoy::Event::FileEventImpl::mergeInjectedEventsAndRunCb() [0x558d8e394eb5]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:123] #10: [0x558d8e710823]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #11: event_base_loop [0x558d8e70d4a1]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #12: Envoy::Server::InstanceBase::run() [0x558d8daa2b99]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #13: Envoy::MainCommonBase::run() [0x558d8da4327a]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #14: Envoy::MainCommon::main() [0x558d8da44234]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #15: main [0x558d8afcc11c]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:123] #16: [0x7f1d54073efb]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #17: __libc_start_main [0x7f1d54073fbb]
Dec 11 00:11:30 dbletE9433T node-envoy[234999]: [2025-12-11 00:11:30.135][234999][critical][backtrace] [./source/server/backtrace.h:121] #18: _start [0x558d8afcc02e]

In this change, we are making the inotify and kqueue watchers handle callback errors gracefully by catching any exceptions using TRY_ASSERT_MAIN_THREAD, logging errors instead of propagating them and always returning the OkStatus to the event loop.

---

Commit Message: filesystem: Fix crash when watch callback returns error or throws
Additional Description: Make inotify and kqueue watchers handle callback errors gracefully.
Risk Level: Low
Testing: CI
Docs Changes: N/A
Release Notes: N/A

Request variables

Key	Value
ref	a6decdc
sha	bd9bd56
pr	42554
base-sha	901d8ce
actor	@agrawroh
message	filesystem: Fix crash when watch callback returns error or throws...
started	1765828550.877112
target-branch	main
trusted	false

Container image/s (as used in this CI run)

Envoy version (as used in this CI run)