[Linux] fix: make textures thread-safe on linux #40478

Kingtous · 2023-03-21T03:47:36Z

We've encountered some memory corruption when developing RustDesk, which is an open-source remote desktop built with Flutter, and it uses the texture API provided by Flutter to provide the remote screen to clients.

Both Windows and macOS work well, except for Linux. Sometimes random crashes will show and print different stack traces in these conditions:

after registering a new texture
preparing a RGBA data and markAvaliable

The runtime often complains double free or corruption.
One of the stack traces using lldb-10:

We checked the implementation of calling textures API on Linux several times, but have no luck.

We've noticed that on Linux, textures are organized by g_hash_table, which is not the thread-safe hashtable and we should ensure synchronization on different threads. Also, we noticed the textures map on Windows already has the synchronization (for example

engine/shell/platform/windows/flutter_windows_texture_registrar.cc

Lines 87 to 90 in 2c342a8

    
           { 
        
             std::lock_guard<std::mutex> lock(map_mutex_); 
        
             auto it = textures_.find(texture_id); 
        
             if (it != textures_.end()) {

). So the implementation on Linux lacks this synchronization on textures management.

We add the synchronization by declaring a GMutex, which is a mutex provided by GTK, in this PR. It can make g_hash_table thread-safe in different threads(ui, raster, etc).

Pre-launch Checklist

I read the Contributor Guide and followed the process outlined there for submitting PRs.
I read the Tree Hygiene wiki page, which explains my responsibilities.
I read and followed the Flutter Style Guide and the C++, Objective-C, Java style guides.
I listed at least one issue that this PR fixes in the description above.
I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt. See testing the engine for instructions on writing and running engine tests.
I updated/added relevant documentation (doc comments with ///).
I signed the CLA.
All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

flutter-dashboard · 2023-03-21T03:47:39Z

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat (don't just cc him here, he won't see it! He's on Discord!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

robert-ancell

Change looks good, thanks! Just some details.

shell/platform/linux/fl_texture_registrar.cc

shell/platform/linux/fl_texture_registrar_test.cc

flutter-dashboard · 2023-03-31T02:46:49Z

Golden file changes have been found for this pull request. Click here to view and triage (e.g. because this is an intentional change).

If you are still iterating on this change and are not ready to resolve the images on the Flutter Gold dashboard, consider marking this PR as a draft pull request above. You will still be able to view image results on the dashboard, commenting will be silenced, and the check will not try to resolve itself until marked ready for review.

Changes reported for pull request #40478 at sha d27e24e

shell/platform/linux/fl_texture_registrar.cc

shell/platform/linux/fl_texture_registrar_private.h

shell/platform/linux/fl_texture_registrar_test.cc

flutter-dashboard · 2023-03-31T05:02:04Z

Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #40478 at sha 665e35a

flutter-dashboard · 2023-03-31T07:13:49Z

Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #40478 at sha 2f14fa7

robert-ancell

Changes look great now, thanks!

…gine#40478)

flutter-dashboard bot added the platform-linux label Mar 21, 2023

flutter-dashboard bot added the needs tests label Mar 21, 2023

Kingtous force-pushed the fix/texture_linux_thread_safe branch 5 times, most recently from 7244d58 to 6cc750d Compare March 21, 2023 07:00

Kingtous changed the title ~~fix: make textures thread-safe on linux~~ [Linux] fix: make textures thread-safe on linux Mar 21, 2023

loic-sharma added the affects: desktop label Mar 23, 2023

cbracken requested review from cbracken and robert-ancell March 30, 2023 18:13

robert-ancell suggested changes Mar 30, 2023

View reviewed changes

shell/platform/linux/fl_texture_registrar.cc Outdated Show resolved Hide resolved

shell/platform/linux/fl_texture_registrar.cc Outdated Show resolved Hide resolved

shell/platform/linux/fl_texture_registrar_test.cc Outdated Show resolved Hide resolved

Kingtous added 3 commits March 31, 2023 09:18

fix: make textures g_hash_table thread-safe

d1a64dd

feat: add tests for mutex

2c290e3

opt: move the mutex into impl

d27e24e

Kingtous force-pushed the fix/texture_linux_thread_safe branch from 3d5a544 to d27e24e Compare March 31, 2023 01:18

flutter-dashboard bot added the will affect goldens label Mar 31, 2023

Kingtous force-pushed the fix/texture_linux_thread_safe branch 2 times, most recently from 69884cc to 8d32cc7 Compare March 31, 2023 03:55

robert-ancell reviewed Mar 31, 2023

View reviewed changes

shell/platform/linux/fl_texture_registrar.cc Outdated Show resolved Hide resolved

robert-ancell reviewed Mar 31, 2023

View reviewed changes

shell/platform/linux/fl_texture_registrar_private.h Outdated Show resolved Hide resolved

Kingtous force-pushed the fix/texture_linux_thread_safe branch from 8d32cc7 to ba7423e Compare March 31, 2023 04:01

robert-ancell suggested changes Mar 31, 2023

View reviewed changes

shell/platform/linux/fl_texture_registrar_test.cc Outdated Show resolved Hide resolved

opt: change test to multiple threads type

665e35a

Kingtous force-pushed the fix/texture_linux_thread_safe branch from ba7423e to 665e35a Compare March 31, 2023 04:06

opt: use lookup

2f14fa7

Kingtous force-pushed the fix/texture_linux_thread_safe branch from 90104b2 to 2f14fa7 Compare March 31, 2023 06:31

robert-ancell approved these changes Apr 2, 2023

View reviewed changes

robert-ancell merged commit f0fa8fd into flutter:main Apr 2, 2023

engine-flutter-autoroll mentioned this pull request Apr 3, 2023

Roll Flutter Engine from 05c14f07f0e5 to f0fa8fdb8add (1 revision) flutter/flutter#123980

Merged

engine-flutter-autoroll added a commit to engine-flutter-autoroll/flutter that referenced this pull request Apr 3, 2023

f0fa8fdb8 [Linux] fix: make textures thread-safe on linux (flutter/en…

68427ab

…gine#40478)

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[Linux] fix: make textures thread-safe on linux #40478

[Linux] fix: make textures thread-safe on linux #40478

Uh oh!

Kingtous commented Mar 21, 2023 •

edited

Loading

Uh oh!

flutter-dashboard bot commented Mar 21, 2023

Uh oh!

robert-ancell left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

Uh oh!

Uh oh!

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

robert-ancell left a comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

	{
	std::lock_guard<std::mutex> lock(map_mutex_);
	auto it = textures_.find(texture_id);
	if (it != textures_.end()) {

[Linux] fix: make textures thread-safe on linux #40478

[Linux] fix: make textures thread-safe on linux #40478

Uh oh!

Conversation

Kingtous commented Mar 21, 2023 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Pre-launch Checklist

Uh oh!

flutter-dashboard bot commented Mar 21, 2023

Uh oh!

robert-ancell left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

Uh oh!

Uh oh!

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

flutter-dashboard bot commented Mar 31, 2023

Uh oh!

robert-ancell left a comment

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Kingtous commented Mar 21, 2023 •

edited

Loading