ACPI: dock: properly initialize local struct dock_station in dock_add()

Commit fe06fba2 (ACPI: dock: add struct dock_station * directly
to platform device data) changed dock_add() to use the
platform_device_register_data() API.

We passed that interface a stack variable, which is kmemdup'ed
and assigned to the device's platform_data pointer.

Unfortunately, whatever random garbage is in the stack variable
gets coped during the kmemdup, and that leads to broken behavior.

Explicitly zero out the structure before passing it to the API.

This fixes the T41 docking button issue:
http://bugzilla.kernel.org/show_bug.cgi?id=15000

Cc: stable@kernel.org
Reported-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index bbc2c1315c473ca7c7e8ff3770506ba645f16f0f..b2586f57e1f5fc1347757cbf24044acbac922a8d 100644 (file)
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -935,6 +935,7 @@ static int dock_add(acpi_handle handle)
        struct platform_device *dd;
 
        id = dock_station_count;
+       memset(&ds, 0, sizeof(ds));
        dd = platform_device_register_data(NULL, "dock", id, &ds, sizeof(ds));
        if (IS_ERR(dd))
                return PTR_ERR(dd);