Re: linux-next: dock_link_device is oopsy

[Holger Macht <holger@homac.de>]

On Fr 17. Feb - 14:42:31, Hugh Dickins wrote:
> On Fri, 17 Feb 2012, Holger Macht wrote:
> > On Fr 17. Feb - 13:46:04, Hugh Dickins wrote:
> > > Matthew,
> > > 
> > > A linux-next oops at bootup in dock_link_device() tells me that you
> > > were not feeling well when you wrote that and dock_unlink_device():
> > > I hope you're feeling better now and can rewrite them soon.
> > 
> > Andrew Morton experienced a similar problem. What system are you using?
> > I didn't encounter this problem with the systems I tested with.
> 
> The two systems I got that on were both 4-year-old Core2 Duo systems,
> one an HP quad desktop, one a Fujitsu-Siemens laptop.

Thanks for the information I think this is really independent from the
fact if a laptop, or more precicely if a system with dock station/bay is
used.

> 
> > 
> > Do you actually have a /sys/devices/platform/dock.?/ directory with a
> > file 'type' that contains 'dock_station'?
> 
> I'll have to report back on that this evening, I'm away from them now.

I actually guess that those systems don't have a
/sys/devices/platform/dock.? directory at all, which is fine.

I also think this will fix it, would be great if you could confirm this:

acpi: Bail out when linking devices and there are no dock stations

If dock_station_count is zero, we allocate zero memory and don't check
this at future references. So bail out if there are actually no dock
stations.

Signed-off-by: Holger Macht <holger@homac.de>
---
 drivers/acpi/dock.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index b5e4142..8641912 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -286,6 +286,9 @@ struct device **dock_link_device(acpi_handle handle)
 	int ret, dock = 0;
 	struct device **devices;
 
+	if (!dock_station_count)
+		return -ENODEV;
+
 	devices = kmalloc(dock_station_count * sizeof(struct device *),
 			  GFP_KERNEL);
 
@@ -323,9 +326,13 @@ struct device **dock_unlink_device(acpi_handle handle)
 	struct device *dev = acpi_get_physical_device(handle);
 	struct dock_station *dock_station;
 	int dock = 0;
-	struct device **devices =
-		kmalloc(dock_station_count * sizeof(struct device *),
-			GFP_KERNEL);
+	struct device **devices;
+
+	if (!dock_station_count)
+		return -ENODEV;
+
+	devices = kmalloc(dock_station_count * sizeof(struct device *),
+			  GFP_KERNEL);
 
 	if (!dev)
 		return NULL;
-- 
1.7.7