Fix segfault race condition at process exit (#5477)

I discovered a couple race conditions leading to segfaults in a separate
repository. After debugging I managed to narrow this down to issues
around the lifetimes of our static global state instances. As these
instances are all destructed as the main thread exits, anything in
separate threads can end up attempting to reuse these instances after
they have been destructed.

The test included in this PR doesn't actually use threads due to
flakiness concerns. Instead we can observe the same phenomenon by
attempting to store a `static std::optional<Context>` instance which
ends up having its destructor run after the destructors for GlobalState
and the root Logger.

This change updates the GlobalState to be a `static
std::shared_ptr<GlobalState>` and the `Logger` to be a `static Logger*`.
In the case of `GlobalState` we then just rely on shared_ptr reference
counting to ensure that the instance is alive for as long as a `Context`
needs it. The `Logger*` on the other hand is just never delete'd so that
any log messages generated are included rather than silencing any thread
after the main thread exits.

---
TYPE: BUG
DESC: Fix segfault race condition at process exit

---------

Co-authored-by: Ryan Roelke <[email protected]>

Author: davisp

tiledb/common/logger.cc

@@ -329,8 +329,12 @@ std::string global_logger_name(const Logger::Format format) {
 }
 
 Logger& global_logger(Logger::Format format) {
-  static Logger l(global_logger_name(format), Logger::Level::ERR, format, true);
-  return l;
+  // Note: We are *not* deallocating this root `Logger` instance so that
+  // during process exit, threads other than main will not trigger segfault's
+  // if they attempt to log after the main thread has exited.
+  static Logger* l = tiledb_new<Logger>(
+      HERE(), global_logger_name(format), Logger::Level::ERR, format, true);
+  return *l;
 }
 
 /** Logs a trace. */

tiledb/sm/cpp_api/config.h

@@ -38,6 +38,7 @@
 
 #include <map>
 #include <memory>
+#include <optional>
 #include <string>
 #include <unordered_map>
 

tiledb/sm/global_state/global_state.cc

@@ -47,9 +47,9 @@ using namespace tiledb::common;
 
 namespace tiledb::sm::global_state {
 
-GlobalState& GlobalState::GetGlobalState() {
+shared_ptr<GlobalState> GlobalState::GetGlobalState() {
   // This is thread-safe in C++11.
-  static GlobalState globalState;
+  static shared_ptr<GlobalState> globalState = make_shared<GlobalState>(HERE());
   return globalState;
 }
 

tiledb/sm/global_state/global_state.h

@@ -37,6 +37,7 @@
 #include <set>
 #include <string>
 
+#include "tiledb/common/common.h"
 #include "tiledb/sm/config/config.h"
 #include "tiledb/sm/storage_manager/storage_manager_declaration.h"
 
@@ -59,8 +60,11 @@ class GlobalState {
   GlobalState& operator=(const GlobalState&) = delete;
   GlobalState& operator=(const GlobalState&&) = delete;
 
+  /** Constructor. */
+  GlobalState();
+
   /** Returns a reference to the singleton GlobalState instance. */
-  static GlobalState& GetGlobalState();
+  static shared_ptr<GlobalState> GetGlobalState();
 
   /**
    * Initializes all TileDB global state in an idempotent and threadsafe way.
@@ -101,9 +105,6 @@ class GlobalState {
 
   /** Mutex protecting list of StorageManagers. */
   std::mutex storage_managers_mtx_;
-
-  /** Constructor. */
-  GlobalState();
 };
 
 }  // namespace global_state

tiledb/sm/global_state/watchdog.cc

@@ -73,13 +73,15 @@ void Watchdog::watchdog_thread(Watchdog* watchdog) {
     return;
   }
 
+  auto global_state = GlobalState::GetGlobalState();
+
   while (true) {
     std::unique_lock<std::mutex> lck(watchdog->mtx_);
     watchdog->cv_.wait_for(
         lck, std::chrono::milliseconds(constants::watchdog_thread_sleep_ms));
 
     if (SignalHandlers::signal_received()) {
-      for (auto* sm : GlobalState::GetGlobalState().storage_managers()) {
+      for (auto* sm : global_state->storage_managers()) {
         throw_if_not_ok(sm->cancel_all_tasks());
       }
     }

tiledb/sm/global_state/watchdog.h

@@ -37,6 +37,8 @@
 #include <mutex>
 #include <thread>
 
+#include "tiledb/sm/global_state/global_state.h"
+
 namespace tiledb {
 namespace sm {
 namespace global_state {

tiledb/sm/storage_manager/CMakeLists.txt

@@ -33,3 +33,5 @@ commence(object_library context_resources)
     this_target_sources(context_resources.cc)
     this_target_object_libraries(baseline config rest_client stats thread_pool vfs)
 conclude(object_library)
+
+add_test_subdirectory()

tiledb/sm/storage_manager/storage_manager.cc

@@ -60,18 +60,17 @@ StorageManagerCanonical::StorageManagerCanonical(
     ContextResources& resources,
     const shared_ptr<Logger>&,  // unused
     const Config& config)
-    : vfs_(resources.vfs())
+    : global_state_(global_state::GlobalState::GetGlobalState())
+    , vfs_(resources.vfs())
     , cancellation_in_progress_(false)
     , config_(config)
     , queries_in_progress_(0) {
-  auto& global_state = global_state::GlobalState::GetGlobalState();
-  global_state.init(config_);
-
-  global_state.register_storage_manager(this);
+  global_state_->init(config_);
+  global_state_->register_storage_manager(this);
 }
 
 StorageManagerCanonical::~StorageManagerCanonical() {
-  global_state::GlobalState::GetGlobalState().unregister_storage_manager(this);
+  global_state_->unregister_storage_manager(this);
 
   throw_if_not_ok(cancel_all_tasks());
 

tiledb/sm/storage_manager/storage_manager_canonical.h

@@ -52,6 +52,7 @@
 #include "tiledb/sm/array/array_directory.h"
 #include "tiledb/sm/enums/walk_order.h"
 #include "tiledb/sm/filesystem/uri.h"
+#include "tiledb/sm/global_state/global_state.h"
 #include "tiledb/sm/group/group.h"
 #include "tiledb/sm/misc/cancelable_tasks.h"
 #include "tiledb/sm/misc/types.h"
@@ -146,6 +147,9 @@ class StorageManagerCanonical {
   /*        PRIVATE ATTRIBUTES         */
   /* ********************************* */
 
+  /** The GlobalState to use for this StorageManager. */
+  shared_ptr<global_state::GlobalState> global_state_;
+
   /**
    * VFS instance used in `cancel_all_tasks`.
    */

tiledb/sm/storage_manager/test/CMakeLists.txt

@@ -0,0 +1,35 @@
+#
+# tiledb/sm/storage_manager/CMakeLists.txt
+#
+# The MIT License
+#
+# Copyright (c) 2025 TileDB, Inc.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+include(unit_test)
+
+commence(unit_test static_context)
+    this_target_sources(main.cc unit_static_context.cc)
+    target_include_directories(unit_static_context PRIVATE
+        "$<TARGET_PROPERTY:TILEDB_CORE_OBJECTS,INCLUDE_DIRECTORIES>")
+    this_target_link_libraries(TILEDB_CORE_OBJECTS)
+    this_target_link_libraries(tiledb_test_support_lib)
+conclude(unit_test)