fix(diagnostics): add render-phase crash markers and improve signal handling

Add signal-safe render-phase markers throughout GameScreen::render() and
Application::render() so the crash handler can report which render call was
active when a SIGSEGV occurs. The AMD RADV crash backtrace only shows 2
frames due to missing frame pointers, making it impossible to identify the
actual crash site.

Changes:
- Add volatile g_crashRenderPhase marker updated before each major render call
- Upgrade Linux signal handler to sigaction with SA_SIGINFO for faulting address
- Set ImGui CheckVkResultFn to log silent Vulkan errors in ImGui backend
- Enable -fno-omit-frame-pointer in all build configs (not just Debug/RelWithDebInfo)

CMakeLists.txt

@@ -935,9 +935,11 @@ else()
     # -g3          — maximum DWARF debug info (includes macro definitions)
     # -Og          — optimise for debugging (better than -O0, keeps most frames)
     # -fno-omit-frame-pointer — preserve frame pointers so stack traces are clean
+    # Frame pointers in all configs (negligible perf cost, critical for crash backtraces)
     target_compile_options(wowee PRIVATE
-        $<$<CONFIG:Debug>:-g3 -Og -fno-omit-frame-pointer>
-        $<$<CONFIG:RelWithDebInfo>:-g -fno-omit-frame-pointer>
+        -fno-omit-frame-pointer
+        $<$<CONFIG:Debug>:-g3 -Og>
+        $<$<CONFIG:RelWithDebInfo>:-g>
     )
 endif()
 

src/core/application.cpp

@@ -2133,15 +2133,22 @@ void Application::update(float deltaTime) {
     }
 }
 
+// Render-phase marker from game_screen.cpp — updated here for 3D/submit phases
+} } // close wowee::core temporarily
+extern volatile const char* g_crashRenderPhase;
+namespace wowee { namespace core {
+
 void Application::render() {
     if (!renderer) {
         return;
     }
 
+    g_crashRenderPhase = "beginFrame";
     renderer->beginFrame();
 
     // Only render 3D world when in-game
     if (state == AppState::IN_GAME) {
+        g_crashRenderPhase = "renderWorld";
         if (world) {
             renderer->renderWorld(world.get(), gameHandler.get());
         } else {
@@ -2151,15 +2158,19 @@ void Application::render() {
 
     // Render performance HUD (within ImGui frame, before UI ends the frame)
     if (renderer) {
+        g_crashRenderPhase = "renderHUD";
         renderer->renderHUD();
     }
 
     // Render UI on top (ends ImGui frame with ImGui::Render())
     if (uiManager) {
+        g_crashRenderPhase = "uiRender";
         uiManager->render(state, authHandler.get(), gameHandler.get());
     }
 
+    g_crashRenderPhase = "endFrame";
     renderer->endFrame();
+    g_crashRenderPhase = "idle";
 }
 
 void Application::setupUICallbacks() {

src/main.cpp

@@ -10,6 +10,7 @@
 #include <X11/Xlib.h>
 #include <execinfo.h>
 #include <unistd.h>
+#include <cstring>
 
 // Keep a persistent X11 connection for emergency mouse release in signal handlers.
 // XOpenDisplay inside a signal handler is unreliable, so we open it once at startup.
@@ -26,32 +27,45 @@ static void releaseMouseGrab() {
 static void releaseMouseGrab() {}
 #endif
 
+// Render-phase marker set by GameScreen::render() — lets crash handler
+// identify which render call was active when backtrace is incomplete.
+extern volatile const char* g_crashRenderPhase;
+
+#ifdef __linux__
+static void crashHandlerSigaction(int sig, siginfo_t* info, void* /*ucontext*/) {
+    releaseMouseGrab();
+    void* frames[64];
+    int n = backtrace(frames, 64);
+    const char* sigName = (sig == SIGSEGV) ? "SIGSEGV" :
+                          (sig == SIGABRT) ? "SIGABRT" :
+                          (sig == SIGFPE)  ? "SIGFPE"  : "UNKNOWN";
+    const char* phase = (const char*)g_crashRenderPhase;
+    void* faultAddr = info ? info->si_addr : nullptr;
+    fprintf(stderr, "\n=== CRASH: signal %s (%d) renderPhase=%s faultAddr=%p ===\n",
+            sigName, sig, phase ? phase : "?", faultAddr);
+    backtrace_symbols_fd(frames, n, STDERR_FILENO);
+    FILE* f = fopen("/tmp/wowee_debug.log", "a");
+    if (f) {
+        fprintf(f, "\n=== CRASH: signal %s (%d) renderPhase=%s faultAddr=%p ===\n",
+                sigName, sig, phase ? phase : "?", faultAddr);
+        fflush(f);
+        backtrace_symbols_fd(frames, n, fileno(f));
+        fclose(f);
+    }
+    // Re-raise with default handler
+    struct sigaction sa;
+    memset(&sa, 0, sizeof(sa));
+    sa.sa_handler = SIG_DFL;
+    sigaction(sig, &sa, nullptr);
+    raise(sig);
+}
+#else
 static void crashHandler(int sig) {
     releaseMouseGrab();
-#ifdef __linux__
-    // Dump backtrace to debug log
-    {
-        void* frames[64];
-        int n = backtrace(frames, 64);
-        const char* sigName = (sig == SIGSEGV) ? "SIGSEGV" :
-                              (sig == SIGABRT) ? "SIGABRT" :
-                              (sig == SIGFPE)  ? "SIGFPE"  : "UNKNOWN";
-        // Write to stderr and to the debug log file
-        fprintf(stderr, "\n=== CRASH: signal %s (%d) ===\n", sigName, sig);
-        backtrace_symbols_fd(frames, n, STDERR_FILENO);
-        FILE* f = fopen("/tmp/wowee_debug.log", "a");
-        if (f) {
-            fprintf(f, "\n=== CRASH: signal %s (%d) ===\n", sigName, sig);
-            fflush(f);
-            // Also write backtrace to the log file fd
-            backtrace_symbols_fd(frames, n, fileno(f));
-            fclose(f);
-        }
-    }
-#endif
     std::signal(sig, SIG_DFL);
     std::raise(sig);
 }
+#endif
 
 static wowee::core::LogLevel readLogLevelFromEnv() {
     const char* raw = std::getenv("WOWEE_LOG_LEVEL");
@@ -69,12 +83,25 @@ static wowee::core::LogLevel readLogLevelFromEnv() {
 int main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[]) {
 #ifdef __linux__
     g_emergencyDisplay = XOpenDisplay(nullptr);
-#endif
+    // Use sigaction for SIGSEGV/SIGABRT/SIGFPE to get si_addr (faulting address)
+    {
+        struct sigaction sa;
+        memset(&sa, 0, sizeof(sa));
+        sa.sa_sigaction = crashHandlerSigaction;
+        sa.sa_flags = SA_SIGINFO;
+        sigaction(SIGSEGV, &sa, nullptr);
+        sigaction(SIGABRT, &sa, nullptr);
+        sigaction(SIGFPE,  &sa, nullptr);
+    }
+    std::signal(SIGTERM, [](int) { std::_Exit(1); });
+    std::signal(SIGINT,  [](int) { std::_Exit(1); });
+#else
     std::signal(SIGSEGV, crashHandler);
     std::signal(SIGABRT, crashHandler);
     std::signal(SIGFPE,  crashHandler);
     std::signal(SIGTERM, crashHandler);
     std::signal(SIGINT,  crashHandler);
+#endif
     try {
         wowee::core::Logger::getInstance().setLogLevel(readLogLevelFromEnv());
         LOG_INFO("=== Wowee Native Client ===");

src/rendering/renderer.cpp

@@ -792,6 +792,10 @@ void Renderer::applyMsaaChange() {
     initInfo.ImageCount = vkCtx->getSwapchainImageCount();
     initInfo.PipelineInfoMain.RenderPass = vkCtx->getImGuiRenderPass();
     initInfo.PipelineInfoMain.MSAASamples = vkCtx->getMsaaSamples();
+    initInfo.CheckVkResultFn = [](VkResult err) {
+        if (err != VK_SUCCESS)
+            LOG_ERROR("ImGui Vulkan error: ", static_cast<int>(err));
+    };
     ImGui_ImplVulkan_Init(&initInfo);
 
     LOG_INFO("MSAA change complete");

src/ui/game_screen.cpp

@@ -47,6 +47,11 @@
 #include <cctype>
 #include <chrono>
 #include <ctime>
+
+// Signal-safe render-phase marker — crash handler reads this to identify which
+// render call was active when a SIGSEGV occurs (backtrace is unreliable with
+// -fomit-frame-pointer).
+volatile const char* g_crashRenderPhase = "idle";
 #include <unordered_set>
 
 namespace {
@@ -298,7 +303,7 @@ void GameScreen::render(game::GameHandler& gameHandler) {
     // Process targeting input before UI windows
     processTargetInput(gameHandler);
 
-    // Player unit frame (top-left)
+    g_crashRenderPhase = "playerFrame";
     renderPlayerFrame(gameHandler);
 
     // Pet frame (below player frame, only when player has an active pet)
@@ -353,6 +358,7 @@ void GameScreen::render(game::GameHandler& gameHandler) {
     }
 
     // ---- New UI elements ----
+    g_crashRenderPhase = "actionBar";
     actionBarPanel_.renderActionBar(gameHandler, settingsPanel_, chatPanel_,
         inventoryScreen, spellbookScreen, questLogScreen,
         [this](uint32_t id, pipeline::AssetManager* am) { return getSpellIcon(id, am); });
@@ -362,31 +368,43 @@ void GameScreen::render(game::GameHandler& gameHandler) {
     actionBarPanel_.renderXpBar(gameHandler, settingsPanel_);
     actionBarPanel_.renderRepBar(gameHandler, settingsPanel_);
     auto spellIconFn = [this](uint32_t id, pipeline::AssetManager* am) { return getSpellIcon(id, am); };
+    g_crashRenderPhase = "castBar";
     combatUI_.renderCastBar(gameHandler, spellIconFn);
     renderMirrorTimers(gameHandler);
     combatUI_.renderCooldownTracker(gameHandler, settingsPanel_, spellIconFn);
     renderQuestObjectiveTracker(gameHandler);
+    g_crashRenderPhase = "nameplates";
     renderNameplates(gameHandler);  // player names always shown; NPC plates gated by showNameplates_
+    g_crashRenderPhase = "bgScore";
     combatUI_.renderBattlegroundScore(gameHandler);
     combatUI_.renderRaidWarningOverlay(gameHandler);
     combatUI_.renderCombatText(gameHandler);
     combatUI_.renderDPSMeter(gameHandler, settingsPanel_);
+    g_crashRenderPhase = "durability";
     renderDurabilityWarning(gameHandler);
     renderUIErrors(gameHandler, ImGui::GetIO().DeltaTime);
     toastManager_.renderEarlyToasts(ImGui::GetIO().DeltaTime, gameHandler);
+    g_crashRenderPhase = "partyFrames";
     if (socialPanel_.showRaidFrames_) {
         socialPanel_.renderPartyFrames(gameHandler, chatPanel_, spellIconFn);
     }
+    g_crashRenderPhase = "bossFrames";
     socialPanel_.renderBossFrames(gameHandler, spellbookScreen, spellIconFn);
+    g_crashRenderPhase = "dialogs";
     dialogManager_.renderDialogs(gameHandler, inventoryScreen, chatPanel_);
+    g_crashRenderPhase = "guildRoster";
     socialPanel_.renderGuildRoster(gameHandler, chatPanel_);
     socialPanel_.renderSocialFrame(gameHandler, chatPanel_);
+    g_crashRenderPhase = "buffBar";
     combatUI_.renderBuffBar(gameHandler, spellbookScreen, spellIconFn);
+    g_crashRenderPhase = "lootWindow";
     windowManager_.renderLootWindow(gameHandler, inventoryScreen, chatPanel_);
     windowManager_.renderGossipWindow(gameHandler, chatPanel_);
+    g_crashRenderPhase = "questWindows";
     windowManager_.renderQuestDetailsWindow(gameHandler, chatPanel_, inventoryScreen);
     windowManager_.renderQuestRequestItemsWindow(gameHandler, chatPanel_, inventoryScreen);
     windowManager_.renderQuestOfferRewardWindow(gameHandler, chatPanel_, inventoryScreen);
+    g_crashRenderPhase = "vendorTrainer";
     windowManager_.renderVendorWindow(gameHandler, inventoryScreen, chatPanel_);
     windowManager_.renderTrainerWindow(gameHandler,
         [this](uint32_t id, pipeline::AssetManager* am) { return getSpellIcon(id, am); });
@@ -398,39 +416,48 @@ void GameScreen::render(game::GameHandler& gameHandler) {
     windowManager_.renderBankWindow(gameHandler, inventoryScreen, chatPanel_);
     windowManager_.renderGuildBankWindow(gameHandler, inventoryScreen, chatPanel_);
     windowManager_.renderAuctionHouseWindow(gameHandler, inventoryScreen, chatPanel_);
+    g_crashRenderPhase = "dungeonFinder";
     socialPanel_.renderDungeonFinderWindow(gameHandler, chatPanel_);
     windowManager_.renderInstanceLockouts(gameHandler);
     socialPanel_.renderWhoWindow(gameHandler, chatPanel_);
+    g_crashRenderPhase = "combatLog";
     combatUI_.renderCombatLog(gameHandler, spellbookScreen);
+    g_crashRenderPhase = "achievementSkills";
     windowManager_.renderAchievementWindow(gameHandler);
     windowManager_.renderSkillsWindow(gameHandler);
     windowManager_.renderTitlesWindow(gameHandler);
     windowManager_.renderEquipSetWindow(gameHandler);
     windowManager_.renderGmTicketWindow(gameHandler);
+    g_crashRenderPhase = "inspectBook";
     socialPanel_.renderInspectWindow(gameHandler, inventoryScreen);
     windowManager_.renderBookWindow(gameHandler);
+    g_crashRenderPhase = "threatBg";
     combatUI_.renderThreatWindow(gameHandler);
     combatUI_.renderBgScoreboard(gameHandler);
+    g_crashRenderPhase = "minimap";
     if (showMinimap_) {
         renderMinimapMarkers(gameHandler);
     }
+    g_crashRenderPhase = "deathLogout";
     windowManager_.renderLogoutCountdown(gameHandler);
     windowManager_.renderDeathScreen(gameHandler);
     windowManager_.renderReclaimCorpseButton(gameHandler);
     dialogManager_.renderLateDialogs(gameHandler);
     chatPanel_.renderBubbles(gameHandler);
     windowManager_.renderEscapeMenu(settingsPanel_);
+    g_crashRenderPhase = "settings";
     settingsPanel_.renderSettingsWindow(inventoryScreen, chatPanel_, [this]() { saveSettings(); });
     toastManager_.renderLateToasts(gameHandler);
+    g_crashRenderPhase = "weather";
     renderWeatherOverlay(gameHandler);
 
-    // World map (M key toggle handled inside)
+    g_crashRenderPhase = "worldMap";
     renderWorldMap(gameHandler);
 
-    // Quest Log (L key toggle handled inside)
+    g_crashRenderPhase = "questLog";
     questLogScreen.render(gameHandler, inventoryScreen);
 
-    // Spellbook (P key toggle handled inside)
+    g_crashRenderPhase = "spellbook";
     spellbookScreen.render(gameHandler, services_.assetManager);
 
     // Insert spell link into chat if player shift-clicked a spellbook entry
@@ -483,7 +510,7 @@ void GameScreen::render(game::GameHandler& gameHandler) {
         windowManager_.vendorBagsOpened_ = false;
     }
 
-    // Bags (B key toggle handled inside)
+    g_crashRenderPhase = "inventory";
     inventoryScreen.setGameHandler(&gameHandler);
     inventoryScreen.render(gameHandler.getInventory(), gameHandler.getMoneyCopper());
 

src/ui/ui_manager.cpp

@@ -78,6 +78,10 @@ bool UIManager::initialize(core::Window* win) {
     initInfo.ImageCount = vkCtx->getSwapchainImageCount();
     initInfo.PipelineInfoMain.RenderPass = vkCtx->getImGuiRenderPass();
     initInfo.PipelineInfoMain.MSAASamples = vkCtx->getMsaaSamples();
+    initInfo.CheckVkResultFn = [](VkResult err) {
+        if (err != VK_SUCCESS)
+            LOG_ERROR("ImGui Vulkan error: ", static_cast<int>(err));
+    };
 
     ImGui_ImplVulkan_Init(&initInfo);