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

[Guenter Roeck <linux@roeck-us.net>]

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@linaro.org>
> Reported-by: kernel test robot <rong.a.chen@intel.com>
> Cc: stable <stable@vger.kernel.org>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Brendan Higgins <brendanhiggins@google.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: Randy Dunlap <rdunlap@infradead.org>
> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Both patches pass my boot tests on arm64 and arm64be (I didn't test any others).
So, FWIW,

Tested-by: Guenter Roeck <linux@roeck-us.net>

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.

Guenter