diff mbox

[Update,1/6] ACPI / scan: Start matching drivers after trying scan handlers

Message ID 2151922.M630KK6nC3@vostro.rjw.lan (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Rafael J. Wysocki Nov. 4, 2013, 1:30 p.m. UTC 
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI scan handlers should always be attached to struct acpi_device
objects before any ACPI drivers, but there is a window during which
a driver may be attached to a struct acpi_device before checking if
there is a matching scan handler.  Namely, that will happen if an
ACPI driver module is loaded during acpi_bus_scan() right after
the first namespace walk is complete and before the given device
is processed by the second namespace walk.

To prevent that from happening, set the match_driver flags of
struct acpi_device objects right before running device_attach()
for them in acpi_bus_device_attach().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/scan.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)


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Comments

Toshi Kani Nov. 5, 2013, 11:27 p.m. UTC | #1 
On Mon, 2013-11-04 at 14:30 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> ACPI scan handlers should always be attached to struct acpi_device
> objects before any ACPI drivers, but there is a window during which
> a driver may be attached to a struct acpi_device before checking if
> there is a matching scan handler.  Namely, that will happen if an
> ACPI driver module is loaded during acpi_bus_scan() right after
> the first namespace walk is complete and before the given device
> is processed by the second namespace walk.
> 
> To prevent that from happening, set the match_driver flags of
> struct acpi_device objects right before running device_attach()
> for them in acpi_bus_device_attach().
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Toshi Kani <toshi.kani@hp.com>

Thanks,
-Toshi

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diff mbox

Patch

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1676,7 +1676,6 @@  void acpi_init_device_object(struct acpi
 
 void acpi_device_add_finalize(struct acpi_device *device)
 {
-	device->flags.match_driver = true;
 	dev_set_uevent_suppress(&device->dev, false);
 	kobject_uevent(&device->dev.kobj, KOBJ_ADD);
 }
@@ -1915,8 +1914,12 @@  static acpi_status acpi_bus_device_attac
 		return AE_OK;
 
 	ret = acpi_scan_attach_handler(device);
-	if (ret)
-		return ret > 0 ? AE_OK : AE_CTRL_DEPTH;
+	if (ret < 0)
+		return AE_CTRL_DEPTH;
+
+	device->flags.match_driver = true;
+	if (ret > 0)
+		return AE_OK;
 
 	ret = device_attach(&device->dev);
 	return ret >= 0 ? AE_OK : AE_CTRL_DEPTH;