Re: [BUG?] Interrupts enabled after xen_acpi_processor_resume+0x0/0x34 [xen_acpi_processor]

From: Stanislaw Gruszka <sgruszka@redhat.com>
To: David Rientjes <rientjes@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	boris.ostrovsky@oracle.com, david.vrabel@citrix.com,
	Ben Guthro <benjamin.guthro@citrix.com>,
	linux-kernel@vger.kernel.org,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	xen-devel@lists.xensource.com
Subject: Re: [BUG?] Interrupts enabled after xen_acpi_processor_resume+0x0/0x34 [xen_acpi_processor]
Date: Fri, 31 Jan 2014 15:04:51 +0100	[thread overview]
Message-ID: <20140131140451.GB7648@redhat.com> (raw)
In-Reply-To: <20140129082521.GA1362@redhat.com>

On Wed, Jan 29, 2014 at 09:25:21AM +0100, Stanislaw Gruszka wrote:
> > Looks incomplete, what about the kzalloc() in 
> > xen_upload_processor_pm_data() and kcalloc()s in check_acpi_ids()?
> 
> Indeed and additionally from check_acpi_ids() we call
> acpi_walk_namespace(), which also take mutexes. Hence unfortunately
> making xen_upload_processor_pm_data() atomic is not easy, but possibly
> can be done by saving some data in memory after initialization.
> 
> Or perhaps this problem can be solved differently, by not using 
> yscore_ops->resume(), but some other resume callback from core, which
> allow to sleep. Than can require registering dummy device or sysfs
> class, but maybe there are simpler solutions.

Eventually work_struct could be used and scheduled from ->resume()
callback, if there is no dependency between uploading processor PM
data to hypervisor and other actions performed after
syscore_ops->resume();

Thanks
Stanislaw