Memory leak runtime/bin/security_context_win.cc

[yaminet1024]

This tracker is for issues related to:

• Dart core libraries (dart:async, dart:io, etc.)

Dart version and tooling diagnostic info

Dart 3.0.2 (stable) (Unknown timestamp) on "windows_x64" on windows / "Windows 10 Pro" 10.0 (Build 22631) locale is zh-CN

Whether you are using Windows, macOS, or Linux

Windows

problem

I found it when I was looking at the leaks in my Flutter Windows application.

[a-siva]

//cc @aam

[aam]

@yaminet1024 thanks for the report.
Do you have small app that reproduces the problem? Do you have a flutter or standalone dart app? What is the screenshot of? What is that that you use for leak detection?

[yaminet1024]

@yaminet1024 thanks for the report. Do you have small app that reproduces the problem? Do you have a flutter or standalone dart app? What is the screenshot of? What is that that you use for leak detection?

Thank you for your assistance. We use Visual Studio to debug our Flutter application. The screenshot provided is from the Visual Studio debugger focusing on memory usage. You can find more information about this tool at https://learn.microsoft.com/en-us/visualstudio/profiling/memory-usage-without-debugging2?view=vs-2022. I've noticed that the number of Dart SSL objects increases each time I open and close the Flutter windows. I plan to create a Flutter example to illustrate this issue. Additionally, could you guide me on how to debug a windows standalone Dart application to analyze memory?

[aam]

Aha, thanks.

Additionally, could you guide me on how to debug a windows standalone Dart application to analyze memory?

You should be able to run .dart programs from powershell using dart.exe that is part of flutter like so:

C> dart main.dart
/CN=storage.googleapis.com
/C=US/O=Google Trust Services LLC/CN=GTS CA 1C3
dc7198af64b5e40a69b2e8d8998e6d5e9aa02ab7748063d903f1d5887c5b1bcf *dartsdk-windows-x64-release.zip
C>

with main.dart having the following contents

import 'dart:io';

main() {
  HttpClient client = new HttpClient();
  client
      .getUrl(Uri.parse("https://storage.googleapis.com/dart-archive/channels/stable/release/3.2.3/sdk/dartsdk-windows-x64-release.zip.sha256sum"))
      .then((request) => request.close())
      .then((response) {
    print(response.certificate!.subject);
    print(response.certificate!.issuer);
    return response
        .fold<List<int>>(<int>[], (message, data) => message..addAll(data));
  }).then((message) {
    String received = new String.fromCharCodes(message);
    print(received);
    client.close();
  });
}

You can also download dart sdk separately from flutter from https://dart.dev/get-dart/archive

Profiling such apps with Visual Studio would involve launching dart.exe process with main.dart as an argument from Visual Studio.

[yaminet1024]

Aha, thanks.

Additionally, could you guide me on how to debug a windows standalone Dart application to analyze memory?

You should be able to run .dart programs from powershell using dart.exe that is part of flutter like so:

C> dart main.dart
/CN=storage.googleapis.com
/C=US/O=Google Trust Services LLC/CN=GTS CA 1C3
dc7198af64b5e40a69b2e8d8998e6d5e9aa02ab7748063d903f1d5887c5b1bcf *dartsdk-windows-x64-release.zip
C>

with main.dart having the following contents

import 'dart:io';

main() {
  HttpClient client = new HttpClient();
  client
      .getUrl(Uri.parse("https://storage.googleapis.com/dart-archive/channels/stable/release/3.2.3/sdk/dartsdk-windows-x64-release.zip.sha256sum"))
      .then((request) => request.close())
      .then((response) {
    print(response.certificate!.subject);
    print(response.certificate!.issuer);
    return response
        .fold<List<int>>(<int>[], (message, data) => message..addAll(data));
  }).then((message) {
    String received = new String.fromCharCodes(message);
    print(received);
    client.close();
  });
}

You can also download dart sdk separately from flutter from https://dart.dev/get-dart/archive

Profiling such apps with Visual Studio would involve launching dart.exe process with main.dart as an argument from Visual Studio.

Here is the Flutter example that uses image.url, which can reproduce the memory leak issue. You can watch the video to see how to reproduce it

play.mp4

demo_win.zip

[yaminet1024]

https://github.com/dart-lang/sdk/blob/296a7f642eb88007e93afd1cfd2921d62152e939/runtime/bin/security_context_win.cc#L122C9-L122C15

I've identified the issue: if the status is not equal to 0 in the line int status = X509_STORE_add_cert(store, root_cert);, then root_cert is never freed. However, when I call X509_free(root_cert) after X509_STORE_add_cert, X509 will not leak

The function X509_STORE_add_cert increases the reference count for the X509 certificate. If we do not free root_cert, it will always have a reference count remaining. You can refer to the documentation for more details at:

For X509_STORE_add_cert: https://www.openssl.org/docs/man1.1.1/man3/X509_STORE_add_cert.html
For X509_free: https://www.openssl.org/docs/man3.2/man3/X509_free.html

[aam]

Thank you @yaminet1024 , you are right, X509_free(root_cert) call is missing. We should do the freeing right after the call to X509_STORE_add_cert, remove such calls from if (status == 0) then-branch. Do you want to submit a patch?

[yaminet1024]

Thank you @yaminet1024 , you are right, X509_free(root_cert) call is missing. We should do the freeing right after the call to X509_STORE_add_cert, remove such calls from if (status == 0) then-branch. Do you want to submit a patch?

yes, I'd be happy to help! I hope I can be of assistance.

[aam]

Sounds good, see if you can follow https://github.com/dart-lang/sdk/blob/main/CONTRIBUTING.md to create either Github PR or Gerrit patch. Gerrit workflow is what dart sdk dev team uses internally, but might take a little more effort to set up compared to Github workflow.