fix(v3/linux): fix crash on panic in JS-bound Go methods#4856
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WebKit2GTK installs signal handlers after gtk_main() starts, overriding our SA_ONSTACK fix. This causes Go panics (e.g., nil pointer dereference) in JS-bound methods to crash with 'non-Go code set up signal handler without SA_ONSTACK flag'. Fix by deferring signal handler installation via g_idle_add() to run after GTK main loop starts, ensuring we fix handlers AFTER WebKit has installed its own. Fixes #3965
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Caution Review failedThe pull request is closed. WalkthroughA signal-handler installation fix for Linux WebKit compatibility was implemented by deferring handler registration from application initialization to the first WebView creation, ensuring registration occurs after GTK/WebKit initialization completes. Changes
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Adds a test application that can trigger panics from JS-bound Go methods to verify the signal handler fix for issue #3965 works correctly. The test app has buttons to: - Trigger a panic in a goroutine - Trigger an immediate panic - Call a safe method Before the fix, clicking 'Trigger Panic' would crash the app. After the fix, panics are recovered and logged.
…llback Move install_signal_handlers() call to after webkit_web_view_new_with_user_content_manager() to ensure WebKit has finished setting up its signal handlers before we add SA_ONSTACK. The previous g_idle_add approach was still too early - WebKit initialization continues after GTK init. This matches the v2 approach which waits for actual webview creation. Also add documentation about the known Go limitation (golang/go#7227) where signals may still be delivered on the wrong stack in some C interop scenarios.
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Grantmartin2002
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Apr 29, 2026
* fix(v3/linux): fix crash on panic in JS-bound Go methods WebKit2GTK installs signal handlers after gtk_main() starts, overriding our SA_ONSTACK fix. This causes Go panics (e.g., nil pointer dereference) in JS-bound methods to crash with 'non-Go code set up signal handler without SA_ONSTACK flag'. Fix by deferring signal handler installation via g_idle_add() to run after GTK main loop starts, ensuring we fix handlers AFTER WebKit has installed its own. Fixes wailsapp#3965 * test(v3/linux): add test case for signal handler fix Adds a test application that can trigger panics from JS-bound Go methods to verify the signal handler fix for issue wailsapp#3965 works correctly. The test app has buttons to: - Trigger a panic in a goroutine - Trigger an immediate panic - Call a safe method Before the fix, clicking 'Trigger Panic' would crash the app. After the fix, panics are recovered and logged. * chore: remove test case from PR * fix(linux): call signal handler fix after WebKit init, not in idle callback Move install_signal_handlers() call to after webkit_web_view_new_with_user_content_manager() to ensure WebKit has finished setting up its signal handlers before we add SA_ONSTACK. The previous g_idle_add approach was still too early - WebKit initialization continues after GTK init. This matches the v2 approach which waits for actual webview creation. Also add documentation about the known Go limitation (golang/go#7227) where signals may still be delivered on the wrong stack in some C interop scenarios.
This was referenced Jun 2, 2026
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Summary
Problem
When Go code called from JavaScript panics (e.g., nil pointer dereference), the app crashes with:
This happens because:
Solution
Call
install_signal_handlers()AFTERwebkit_web_view_new_with_user_content_manager()returns, ensuring we add SA_ONSTACK to signal handlers AFTER WebKit has installed its own. This matches the approach used in v2.Known Limitation
Note: This fix may not fully resolve all signal-related crashes. There is a known Go runtime limitation (golang/go#7227, open since 2014) where signals may still be delivered on the wrong stack when C libraries (like WebKit/GTK) are involved, even with SA_ONSTACK correctly set. This is a fundamental Go/C interop issue that requires Go runtime changes to fully resolve.
Type of change
How Has This Been Tested?
Fixes #3965
Note: This is the v3 version of the fix. See #4855 for the v2 version.
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