linux-kernel - Re: Acpi deadlocks with 3.7.0-rc4

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Date:	Thu, 29 Nov 2012 11:59:33 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Zdenek Kabelac <zkabelac@...hat.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Len Brown <lenb@...nel.org>,
	Linux ACPI <linux-acpi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Acpi deadlocks with 3.7.0-rc4

On Thursday, November 29, 2012 11:13:10 AM Zdenek Kabelac wrote:
> Dne 28.11.2012 20:07, Linus Torvalds napsal(a):
> > whole "prefix_node" pointer is bogus. It seems to have the value 0x1000.
> 
> Tested also this patch with this result:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=51071#c8
> 
> So while it's made it pass suspend/resume, it's not really usable
> as docking then.

This just makes acpi_ns_lookup() always return acpi_gbl_root_node
for things looked up by acpi_ns_get_node() as far as I can say.

Hmm.

If my theory correct, the patch below should catch the bug.  Can you please
test it?

Rafael


---
 drivers/acpi/scan.c            |    1 +
 drivers/pnp/pnpacpi/rsparser.c |    3 +++
 2 files changed, 4 insertions(+)

Index: linux/drivers/acpi/scan.c
===================================================================
--- linux.orig/drivers/acpi/scan.c
+++ linux/drivers/acpi/scan.c
@@ -704,6 +704,7 @@ static void acpi_device_unregister(struc
 	mutex_unlock(&acpi_device_lock);
 
 	acpi_detach_data(device->handle, acpi_bus_data_handler);
+	device->handle = ERR_PTR(-ENODEV);
 
 	acpi_device_remove_files(device);
 	device_unregister(&device->dev);
Index: linux/drivers/pnp/pnpacpi/rsparser.c
===================================================================
--- linux.orig/drivers/pnp/pnpacpi/rsparser.c
+++ linux/drivers/pnp/pnpacpi/rsparser.c
@@ -611,6 +611,9 @@ int pnpacpi_build_resource_template(stru
 	int res_cnt = 0;
 	acpi_status status;
 
+	if (WARN_ON_ONCE(IS_ERR(handle)))
+		return PTR_ERR(handle);
+
 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
 				     pnpacpi_count_resources, &res_cnt);
 	if (ACPI_FAILURE(status)) {



-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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