Marco Trevisan (Treviño) 7b61cc8277 glib/gmain: Avoid potential dispose race on GSource due to refcount dance
During g_source_unref() we might end up calling dispose from
multiple threads, and due to the ref/unref dance we were doing we could
end up initiating a GSource finalization while another thread was about
to revive the source.

This was because we were unreffing a source in a thread, and potentially
re-reffing it, at the same time, but it was not guaranteed that the
final decrement and test couldn't be followed by a further re-ref.

To avoid this, do not do any ref/unref/re-ref/re-unref dance while we're
about to dispose, but instead follow a bit more the g_object_unref()
logic, and start the disposal phase only if we're about to drop the last
reference, and only after the potential disposal call is done, we do an
actual ref count decrement, which may lead to the finalization or not.

We don't bother following the same logic at later point, since after
disposal we should really have just one thread running and revival of a
finalizing GSource isn't supported anyways.

With this logic we can also avoid doing unneeded context locking when
we've enough references on a GSource that disposal is unlikely to
happen.

Closes: #3612
2025-02-19 18:59:33 +01:00
2024-04-01 11:01:06 +00:00
2023-07-30 17:03:07 +04:00
2025-02-16 17:04:41 +01:00
2019-11-21 14:03:01 -06:00
2021-10-28 14:47:53 +01:00
2024-10-18 14:59:20 +08:00
2025-01-23 13:20:40 +00:00
2024-08-29 08:58:36 +01:00

GLib

GLib is the low-level core library that forms the basis for projects such as GTK and GNOME. It provides data structure handling for C, portability wrappers, and interfaces for such runtime functionality as an event loop, threads, dynamic loading, and an object system.

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Low-level core library that forms the basis for projects such as GTK+ and GNOME.
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