Re: [PATCH 1/2] software node: implement software_node_unregister()

From: Randy Dunlap
Date: Sun May 24 2020 - 22:44:45 EST

On 5/24/20 9:43 AM, Guenter Roeck wrote:
> On 5/24/20 8:30 AM, Greg Kroah-Hartman wrote:
>> Sometimes it is better to unregister individual nodes instead of trying
>> to do them all at once with software_node_unregister_nodes(), so create
>> software_node_unregister() so that you can unregister them one at a
>> time.
>> This is especially important when creating nodes in a hierarchy, with
>> parent -> children representations. Children always need to be removed
>> before a parent is, as the swnode logic assumes this is going to be the
>> case.
>> Fix up the lib/test_printf.c fwnode_pointer() test which to use this new
>> function as it had the problem of tearing things down in the backwards
>> order.
>> Fixes: f1ce39df508d ("lib/test_printf: Add tests for %pfw printk modifier")
>> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
>> Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
>> Cc: stable <stable@xxxxxxxxxxxxxxx>
>> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>> Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
>> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
>> Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
>> Cc: Petr Mladek <pmladek@xxxxxxxx>
>> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
>> Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
>> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Both patches pass my boot tests on arm64 and arm64be (I didn't test any others).
> So, FWIW,
> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> I wasn't sure it the two patches replace or fix commit 4ef12f719802 ("kobject:
> Make sure the parent does not get released before its children"), so I tried
> to re-apply 4ef12f719802 on top of the two patches. Unfortunately that still
> results in crashes and UAF messages.

Yes, that kobject patch has been reverted:

and these 2 patches are to be used instead.