[CP] [vm] Flush thread store buffer block after processing finalizers

[dcharkes]

Commit(s) to merge

78f218e

Target

stable

Issue Description

When Finalizers and NativeFinalizers are used in Flutter (and dart with --use-compactor), the GC can crash.

What is the fix

Flush the store buffer during GC to account for write to the store buffer during the GC.

Why cherry-pick

When Finalizers or NativeFinalizers are used in Flutter apps, those apps can crash.

Without the fix, developers have to work around this by allocating a new Finalizer or NativeFinalizer for every attachment. But we have no way of communicating that to all developers trying out finalizers.

Risk

low

Issue link(s)

#48843

Extra Info

This is a 4 line fix:

https://dart-review.googlesource.com/c/sdk/+/243262/12/runtime/vm/heap/marker.cc
https://dart-review.googlesource.com/c/sdk/+/243262/12/runtime/vm/thread.cc

The rest is tests/logging.

@mraleph @rmacnak-google Would you consider this a low risk cherry pick?

cc @mkustermann

[athomas]

Based on an offline discussion with @mit-mit and @mraleph we're treating this as approved and will prepare a beta build with this CP. We can still decide not to publish this.

@itsjustkevin

[sortie]

I cherry-picked this change as 2.17.0-266.10.beta (fc290d1).