Bug 65130

Summary:	Race condition in GObject interface type registration
Product:	PolicyKit	Reporter:	Tomas Bzatek <bugs>
Component:	libpolkit	Assignee:	David Zeuthen (not reading bugmail) <zeuthen>
Status:	RESOLVED FIXED	QA Contact:	David Zeuthen (not reading bugmail) <zeuthen>
Severity:	major
Priority:	medium	CC:	walters
Version:	unspecified
Hardware:	All
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	[PATCH] Use GOnce for interface type registration

Description Tomas Bzatek 2013-05-29 13:58:38 UTC

Created attachment 79966 [details]
[PATCH] Use GOnce for interface type registration

In certain cases, randomly, udisksd was failing with the following messages:

> (udisksd:10020): GLib-GObject-WARNING **: cannot register existing type `PolkitSubject'
> (udisksd:10020): GLib-GObject-CRITICAL **: g_type_interface_add_prerequisite: assertion `G_TYPE_IS_INTERFACE (interface_type)' failed
> (udisksd:10020): GLib-GObject-WARNING **: invalid cast from `PolkitSystemBusName' to `<invalid>'
> (udisksd:10020): GLib-GObject-WARNING **: cannot register existing type `PolkitSubject'
> (udisksd:10020): GLib-GObject-WARNING **: cannot register existing type `PolkitSubject'
> (udisksd:10020): GLib-GObject-CRITICAL **: g_type_interface_add_prerequisite: assertion `G_TYPE_IS_INTERFACE (interface_type)' failed
> (udisksd:10020): GLib-GObject-CRITICAL **: g_type_interface_add_prerequisite: assertion `G_TYPE_IS_INTERFACE (interface_type)' failed
> ** (udisksd:10020): CRITICAL **: polkit_authority_check_authorization_sync: assertion `POLKIT_IS_SUBJECT (subject)' failed
> ** (udisksd:10020): CRITICAL **: polkit_authority_check_authorization_sync: assertion `POLKIT_IS_SUBJECT (subject)' failed

Further debugging showed missing locking in polkit_subject_get_type() and potential race explaining the first GObject warning.

The attached patch makes the type registration use modern conventions with GOnce.

Comment 1 Colin Walters 2013-05-29 14:14:34 UTC

Looks good.  I amended the patch to include a link back to this bug.

http://cgit.freedesktop.org/polkit/commit/?id=20ad116a6582e57d20f9d8197758947918753a4c

Comment 2 Hans de Goede 2013-05-29 14:34:40 UTC

I can confirm that this patch fixes my reproducable udisksd crashes.

Comment 3 David Zeuthen (not reading bugmail) 2013-05-29 19:23:34 UTC

Nice catch guys, thanks for fixing this!

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