Fix crash if FlView is destroyed during a draw. by robert-ancell · Pull Request #186848 · flutter/flutter

robert-ancell · 2026-05-21T04:58:25Z

Ensure the object remains alive until the redraw callback completes.

Triggered by rapidly opening and closing tooltips in the multi-window demo app. Command line error:
g_mutex_clear() called on uninitialised or locked mutex

flutter-dashboard · 2026-05-21T04:58:30Z

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gemini-code-assist

Code Review

This pull request modifies the lifecycle management of FlView in the Linux platform shell by introducing g_autoptr and explicit object referencing for idle callbacks. Feedback indicates that using g_autoptr within the callback is fragile and could lead to a use-after-free if the callback logic is changed to persist. Additionally, it is recommended to use g_idle_add_full with a GDestroyNotify to ensure the object reference is properly released even if the idle source is removed before execution, preventing potential memory leaks.

gemini-code-assist · 2026-05-21T04:59:35Z

 // Redraw the view from the GTK thread.
 static gboolean redraw_cb(gpointer user_data) {
-  FlView* self = FL_VIEW(user_data);
+  g_autoptr(FlView) self = FL_VIEW(user_data);


Using g_autoptr inside a GSourceFunc to manage the lifecycle of user_data is fragile. If the callback were ever modified to return G_SOURCE_CONTINUE (TRUE), the object would be unreferenced prematurely at the end of the first execution, leading to a use-after-free in subsequent iterations. It is safer to manage the lifecycle via the source's destroy notify in the caller.

FlView* self = FL_VIEW(user_data);

gemini-code-assist · 2026-05-21T04:59:35Z


  // Perform the redraw in the GTK thead.
-  g_idle_add(redraw_cb, self);
+  g_idle_add(redraw_cb, g_object_ref(self));


Using g_idle_add_full with g_object_unref as the GDestroyNotify is the idiomatic and more robust way to manage the lifetime of the user_data object in GLib. This ensures that the reference is released even if the idle source is removed without the callback being executed (e.g., during application shutdown or if the source is explicitly removed), preventing a potential reference leak.

g_idle_add_full(G_PRIORITY_DEFAULT_IDLE, redraw_cb, g_object_ref(self), g_object_unref);

Saviq

Works for me 👍

robert-ancell · 2026-05-24T21:56:32Z

@loic-sharma can you kick off the google testing?

loic-sharma

Approving to run google testing

Ensure the object remains alive until the redraw callback completes. Triggered by rapidly opening and closing tooltips in the multi-window demo app. Command line error: g_mutex_clear() called on uninitialised or locked mutex

mattkae · 2026-05-27T15:31:51Z

Rebased to poke Google testing

flutter/flutter@c8f2f16...e70534d 2026-05-28 [email protected] Linux glyph gamma correction (flutter/flutter#187122) 2026-05-28 [email protected] [iOS] Eliminate strong retain cycle from VSyncClient (flutter/flutter#187164) 2026-05-28 [email protected] Revert "[pubspec] Bump Dart SDK constraint to ^3.13.0 (#186957)" (flutter/flutter#187209) 2026-05-28 [email protected] Roll Skia from f1b8ba877c07 to 32acea791248 (3 revisions) (flutter/flutter#187220) 2026-05-27 [email protected] Roll Fuchsia Linux SDK from k9EizfEGJO4WwQN9-... to SBpmmPxqx3lAvGojE... (flutter/flutter#187211) 2026-05-27 [email protected] [Impeller] Add block-compressed texture format support (BC, ETC2, ASTC) (flutter/flutter#187077) 2026-05-27 [email protected] Disable analyzer (flutter/flutter#187205) 2026-05-27 [email protected] [Flutter GPU] Add explicit draw counts (reland) (flutter/flutter#187192) 2026-05-27 [email protected] [Flutter GPU] Inject per-backend defines into shader bundle compilation (flutter/flutter#187081) 2026-05-27 [email protected] Roll Skia from fa944af10f91 to f1b8ba877c07 (13 revisions) (flutter/flutter#187194) 2026-05-27 [email protected] Fixes bug when changing accessibilityFocusBlockType doesn't update ch… (flutter/flutter#186596) 2026-05-27 [email protected] Roll pub packages (flutter/flutter#187191) 2026-05-27 [email protected] [web, tool] Support recompiling shaders and unify asset processing (2nd try) (flutter/flutter#186902) 2026-05-27 [email protected] Fix crash if FlView is destroyed during a draw. (flutter/flutter#186848) 2026-05-27 [email protected] Roll Packages from fc795e5 to 4b424d7 (4 revisions) (flutter/flutter#187174) 2026-05-27 [email protected] Stop prefetching Swift packages in pub get (flutter/flutter#187113) 2026-05-27 [email protected] Update CI with newer android sdk package (flutter/flutter#187143) 2026-05-27 [email protected] Add a tag to the Linux platform properties in .ci.yaml that specifies x64 CPUs (flutter/flutter#187124) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

robert-ancell requested a review from a team as a code owner May 21, 2026 04:58

flutter-dashboard Bot added the CICD Run CI/CD label May 21, 2026

github-actions Bot added engine flutter/engine related. See also e: labels. platform-linux Building on or for Linux specifically a: desktop Running on desktop team-linux Owned by the Linux platform team labels May 21, 2026

robert-ancell requested a review from mattkae May 21, 2026 04:58

gemini-code-assist Bot reviewed May 21, 2026

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Saviq reviewed May 21, 2026

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mattkae approved these changes May 21, 2026

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mattkae force-pushed the linux-redraw-during-view-removal branch from e53b51f to fd4473b Compare May 21, 2026 20:39

mattkae enabled auto-merge May 21, 2026 20:40

github-actions Bot removed the CICD Run CI/CD label May 21, 2026

robert-ancell requested a review from loic-sharma May 24, 2026 21:56

loic-sharma approved these changes May 24, 2026

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Fix crash if FlView is destroyed during a draw.

d5312e4

Ensure the object remains alive until the redraw callback completes. Triggered by rapidly opening and closing tooltips in the multi-window demo app. Command line error: g_mutex_clear() called on uninitialised or locked mutex

mattkae force-pushed the linux-redraw-during-view-removal branch from fd4473b to d5312e4 Compare May 27, 2026 15:31

flutter-dashboard Bot added the CICD Run CI/CD label May 27, 2026

mattkae added this pull request to the merge queue May 27, 2026

Merged via the queue into flutter:master with commit becb399 May 27, 2026
207 of 208 checks passed

engine-flutter-autoroll mentioned this pull request May 28, 2026

Roll Flutter from c8f2f166323e to e70534db5a44 (18 revisions) flutter/packages#11799

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Fix crash if FlView is destroyed during a draw.#186848

Fix crash if FlView is destroyed during a draw.#186848
mattkae merged 1 commit into
flutter:masterfrom
robert-ancell:linux-redraw-during-view-removal

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