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Subject[PATCH 4.9 10/16] ACPI: power: Skip duplicate power resource references in _PRx
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@redhat.com>

commit 7d7b467cb95bf29597b417d4990160d4ea6d69b9 upstream.

Some ACPI tables contain duplicate power resource references like this:

Name (_PR0, Package (0x04) // _PR0: Power Resources for D0
{
P28P,
P18P,
P18P,
CLK4
})

This causes a WARN_ON in sysfs_add_link_to_group() because we end up
adding a link to the same acpi_device twice:

sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/808622C1:00/OVTI2680:00/power_resources_D0/LNXPOWER:0a'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.12-301.fc29.x86_64 #1
Hardware name: Insyde CherryTrail/Type2 - Board Product Name, BIOS jumperx.T87.KFBNEEA02 04/13/2016
Call Trace:
dump_stack+0x5c/0x80
sysfs_warn_dup.cold.3+0x17/0x2a
sysfs_do_create_link_sd.isra.2+0xa9/0xb0
sysfs_add_link_to_group+0x30/0x50
acpi_power_expose_list+0x74/0xa0
acpi_power_add_remove_device+0x50/0xa0
acpi_add_single_object+0x26b/0x5f0
acpi_bus_check_add+0xc4/0x250
...

To address this issue, make acpi_extract_power_resources() check for
duplicates and simply skip them when found.

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Subject & changelog, comments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/power.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -131,6 +131,23 @@ void acpi_power_resources_list_free(stru
}
}

+static bool acpi_power_resource_is_dup(union acpi_object *package,
+ unsigned int start, unsigned int i)
+{
+ acpi_handle rhandle, dup;
+ unsigned int j;
+
+ /* The caller is expected to check the package element types */
+ rhandle = package->package.elements[i].reference.handle;
+ for (j = start; j < i; j++) {
+ dup = package->package.elements[j].reference.handle;
+ if (dup == rhandle)
+ return true;
+ }
+
+ return false;
+}
+
int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
struct list_head *list)
{
@@ -150,6 +167,11 @@ int acpi_extract_power_resources(union a
err = -ENODEV;
break;
}
+
+ /* Some ACPI tables contain duplicate power resource references */
+ if (acpi_power_resource_is_dup(package, start, i))
+ continue;
+
err = acpi_add_power_resource(rhandle);
if (err)
break;

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