[vm] Allow to skip crash handler installation in bin::Platform::Initialize. by Arbaaz123676 · Pull Request #62680 · dart-lang/sdk

Arbaaz123676 · 2026-02-15T15:25:56Z

Summary

On macOS, writing to a closed exit pipe can deliver SIGPIPE which terminates the process even when EPIPE is handled correctly.

This change temporarily blocks SIGPIPE while writing the exit code in "ExitCodeHandlerEntry". This ensures that failed "Process.start" calls do not trigger unintended process termination.

The signal mask is scoped only around the write operation to keep the behaviour localized and avoid affecting global signal handling.

Platform: macOS only

Fixes: #62679.

copybara-service · 2026-02-15T15:28:06Z

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mraleph · 2026-02-15T15:42:37Z

There is already code in Platform::Initialize which does this. I would expect it is called by Flutter engine. This means something later messes it up.

Arbaaz123676 · 2026-02-15T16:36:24Z

Hi @mraleph, Thanks for the pointer! That makes sense — I added the masking here because I observed SIGPIPE during the exit pipe write path on macOS, but if Platform::Initialize already configures it, then something later must be modifying the mask.

I’ll investigate where SIGPIPE handling may be reset after initialization. Do you have a recommended area to check (Flutter embedder vs VM runtime), or should I go with tracing signal mask changes around process start?

Happy to adjust the approach based on the intended design.

mraleph · 2026-02-16T08:21:23Z

See my comment here: #62679 (comment)

copybara-service · 2026-02-16T09:39:37Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T09:39:58Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

mraleph · 2026-02-16T09:43:18Z

-  if (sigaction(SIGILL, &act, nullptr) != 0) {
-    perror("sigaction() failed.");
-    return false;
+  if (install_crash_handler){


Not properly formatted: missing space here.

In general, I'd recommend running git cl format to make sure that all code is properly formatted.

mraleph · 2026-02-16T09:43:39Z

          int message[2] = {exit_code, negative};
-          ssize_t result =
-              FDUtils::WriteToBlocking(exit_code_fd, &message, sizeof(message));
+          ssize_t result = 


Fully revert changes to this file as they are not necessary.

mraleph · 2026-02-16T09:44:55Z

The title of this PR should probably be updated to match what we are doing here.

copybara-service · 2026-02-16T10:21:39Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T10:24:37Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T10:25:06Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

mraleph

A better name for the PR is: [vm] Allow to skip crash handler installation in bin::Platform::Initialize

mraleph · 2026-02-16T10:44:47Z

 }

-bool Platform::Initialize() {
+bool Platform::Initialize(bool install_crash_handler) {


We would usually write bool install_crash_hander /* = true */ to make default value obvious (otherwise reader must go to declaration to see it).

You need to modify all platform specific Platform::Initialize implementations in all runtime/bin/platform_*.cc files in the same way. Otherwise the build will break.

Just to confirm before I proceed — since we changed the signature of Platform::Initialize in platform.h, do you want me to update the function signature to Initialize(bool install_crash_handler /*= true */) across all platform-specific implementations (platform_linux.cc, platform_win.cc, platform_fuchsia.cc, platform.cc) as well, without changing their logic?

Not changing the logic would be inconsistent. They should all do the same thing, so they should all get the additional parameter and respect that parameter.

copybara-service · 2026-02-16T10:49:47Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T11:09:13Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T11:09:36Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

mraleph · 2026-02-16T11:34:44Z

 }

-bool Platform::Initialize() {
+bool Platform::Initialize(bool install_crash_handler /* = true */) {


This should be the same as Mac OS X version, but it is not updated for some reason and just ignores the parameter.

mraleph · 2026-02-16T11:36:36Z


-bool Platform::Initialize() {
+bool Platform::Initialize(bool install_crash_handler /* = true */) {
  PlatformWin::InitOnce();


PlatformWin::InitOnce installs crash handler. So it should probably respect install_crash_handler.

copybara-service · 2026-02-16T12:02:48Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-16T12:02:49Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

mraleph · 2026-02-17T09:07:02Z

I think we want to if (install_crash_handler) just this one. Not other things in this function.

copybara-service · 2026-02-17T09:58:46Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

copybara-service · 2026-02-17T10:03:13Z

https://dart-review.googlesource.com/c/sdk/+/480880 has been updated with the latest commits from this pull request.

Arbaaz123676 · 2026-02-17T12:33:22Z

@mraleph, Updated macOS, Linux and Windows implementations to consistently respect "install_crash_handler". Only crash handler setup is conditional now.

Please let me know if anything else needs adjustment.

mraleph · 2026-02-17T12:49:29Z

I have merged the CL. Thanks for the contribution. Now we need to figure what to do with Flutter embedder. It should just call dart::bin::Platform::Init(/*install_crash_handler=*/false) somewhere.

Arbaaz123676 · 2026-02-17T13:05:38Z

What if we add a call to dart::bin::Platform::Init(false) during Flutter engine VM initialization (maybe in dart_vm.cc) before Dart runtime startup, so Flutter fully owns the crash handling?

mraleph · 2026-02-17T13:13:10Z

Yeah, something like that. You should ask Flutter engine folks what's the best place to put it in.

Arbaaz123676 · 2026-02-17T13:18:57Z

Thanks! I’m not very familiar yet with the Flutter engine workflow — should I open an issue in the Flutter engine repo about where to place the dart::bin::Platform::Init(false) call. or is there a specific place you recommend reaching out to?

mraleph · 2026-02-17T13:28:00Z

@Arbaaz123676 you can start by asking on Flutter Discord.

Arbaaz123676 · 2026-02-20T04:58:42Z

Hello @mraleph — one of the Flutter contributors replied with:
“Flutter does not currently call dart::bin::Platform::Initialize().

Calling Platform::Initialize(false) within the DartVM constructor in https://github.com/flutter/flutter/blob/master/engine/src/flutter/runtime/dart_vm.cc seems reasonable. I can try to build a PR to do this next week.

I’m not sure whether any OS-specific Platform::Initialize implementations might introduce undesirable side effects on some target platforms (such as Android). If so, we may need to exclude it on certain platforms.”

Based on this, I’m planning to open an issue in the Flutter repository (https://github.com/flutter/flutter/issues) also with reference of the related Dart issue (#62679) as well as the PR (#62680) for context.

I would really appreciate your guidance on whether this is the right place to track it and if there’s anything specific I should consider before opening the issue. Thank you!

This does platform-specific setup for Dart (such as configuring signal handlers) Fixes flutter#182436 See dart-lang/sdk#62679 See dart-lang/sdk#62680

This does platform-specific setup for Dart (such as configuring signal handlers) Fixes #182436 See dart-lang/sdk#62679 See dart-lang/sdk#62680

…182689) This does platform-specific setup for Dart (such as configuring signal handlers) Fixes flutter#182436 See dart-lang/sdk#62679 See dart-lang/sdk#62680

[vm] Mask SIGPIPE during exit pipe write on macOS

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mraleph requested changes Feb 16, 2026

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Arbaaz123676 changed the title ~~[vm] Mask SIGPIPE during exit pipe write on macOS.~~ [vm] Respect install_crash_handler in Platform::Initialize on macOS. Feb 16, 2026

Arbaaz123676 force-pushed the fix-macos-sigpipe-process-start branch from 1145ba9 to e77016d Compare February 16, 2026 10:22

mraleph requested changes Feb 16, 2026

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Arbaaz123676 changed the title ~~[vm] Respect install_crash_handler in Platform::Initialize on macOS.~~ [vm] Allow to skip crash handler installation in bin::Platform::Initialize. Feb 16, 2026

Arbaaz123676 force-pushed the fix-macos-sigpipe-process-start branch from e77016d to 5efabee Compare February 16, 2026 11:06

mraleph reviewed Feb 16, 2026

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Arbaaz123676 force-pushed the fix-macos-sigpipe-process-start branch from 5efabee to b79fda3 Compare February 16, 2026 12:00

mraleph reviewed Feb 17, 2026

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[vm] Respect Platform::Initialize for SIGPIPE handling on macOS

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Arbaaz123676 force-pushed the fix-macos-sigpipe-process-start branch from b79fda3 to deeed63 Compare February 17, 2026 09:56

copybara-service Bot closed this in e2c278d Feb 17, 2026

jason-simmons mentioned this pull request Feb 20, 2026

Call dart::bin::Platform::Initialize during Dart VM startup flutter/flutter#182689

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Arbaaz123676 commented Feb 15, 2026

Summary

Platform: macOS only

Fixes: #62679.

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