Hi Rob,

On 01/13/2015 04:27 PM, Rob Herring wrote:

On Wed, Jan 7, 2015 at 11:30 AM, Suman Anna [off-list ref] wrote:

quoted

Drivers can use of_platform_populate() to create platform devices
for children of the device main node, and a complementary API
of_platform_depopulate() is provided to delete these child devices.
Any platform_data supplied for the OF devices through auxdata lookup
data is populated directly in the device's platform_data field, unlike
those created using platform API. The of_platform_depopulate()
leverages the platform code for cleanup, and this will result in a
kernel oops due to an invalid kfree on this direct populated
platform_data.

Fix this by resetting the platform data for OF devices during
platform device cleanup.

We should probably copy the platform_data like is done for non-OF
platform devices. I'm sure there was some reason for it. 

Yeah, that was my first thought too, but went with adding a checking
here as I am not aware of the original reason for not copying it, and it
seemed like unnecessary copying of static data without any real gain.

It looks strange doing this in release.

However, I'm inclined to not fix this and force users to move off of
auxdata. That's intended to be a temporary migration path and there
are only 54 instances of it that have platform_data. What device do
you care about?

I use this mainly for the remoteproc devices (mainly differentiating
multiple instances of the same compatible type on the same SoC), but
fair enough, I can rework my driver to use some lookup based match data
instead. So far, none of the drivers who use of_platform_populate() did
supply platform data, so this particular crash is not seen/common.
platform_data does get used in the OMAP pdata-quirks, though
of_platform_depopulate() won't be called on those, as this is called in
init_machine.

regards
Suman

Rob

quoted

Signed-off-by: Suman Anna <redacted>
---
 drivers/base/platform.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9421fed40905..129e69c8c894 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c

@@ -200,6 +200,8 @@ static void platform_device_release(struct device *dev)
        struct platform_object *pa = container_of(dev, struct platform_object,
                                                  pdev.dev);

+       if (pa->pdev.dev.of_node)
+               pa->pdev.dev.platform_data = NULL;
        of_device_node_put(&pa->pdev.dev);
        kfree(pa->pdev.dev.platform_data);
        kfree(pa->pdev.mfd_cell);
--

2.2.1