linux-kernel - Re: [PATCH v1] kobject: make sure parent is not released before children

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Date:   Wed, 15 Apr 2020 11:18:58 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Brendan Higgins <brendanhiggins@...gle.com>
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org,
        linux-kernel@...r.kernel.org, naresh.kamboju@...aro.org,
        sakari.ailus@...ux.intel.com, andy.shevchenko@...il.com,
        hdegoede@...hat.com, rafael.j.wysocki@...el.com,
        linux-kselftest@...r.kernel.org, rostedt@...dmis.org,
        sergey.senozhatsky@...il.com, andriy.shevchenko@...ux.intel.com,
        shuah@...nel.org, anders.roxell@...aro.org,
        lkft-triage@...ts.linaro.org, linux@...musvillemoes.dk
Subject: Re: [PATCH v1] kobject: make sure parent is not released before
 children

On Tue, Apr 14, 2020 at 01:42:40PM -0700, Brendan Higgins wrote:
> From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

This patch isn't from me. You can use a tag like "Proposed-by:
Heikki..." or "Co-developed-by: Heikki..." in cases like this.

> Previously, kobjects were released before the associated kobj_types;
> this can cause a kobject deallocation to fail when the kobject has
> children; an example of this is in software_node_unregister_nodes(); it
> calls release on the parent before children meaning that children can be
> released after the parent, which may be needed for removal.

That makes it sound like it's software_node_unregister_nodes() that is
releasing the parent, which isn't the case.

> So, take a reference to the parent before we delete a node to ensure
> that the parent is not released before the children.
> 
> Reported-by: Naresh Kamboju <naresh.kamboju@...aro.org>
> Fixes: 7589238a8cf3 ("Revert "software node: Simplify software_node_release() function"")
> Link: https://lore.kernel.org/linux-kselftest/CAFd5g44s5NQvT8TG_x4rwbqoa7zWzkV0TX+ETZoQdOB7OwXCPQ@mail.gmail.com/T/#m71f37f3985f2abd7209c8ca8e0fa4edc45e171d6
> Co-developed-by: Brendan Higgins <brendanhiggins@...gle.com>
> Signed-off-by: Brendan Higgins <brendanhiggins@...gle.com>
> ---
> 
> This patch is based on the diff written by Heikki linked above.
> 
> Heikki, can you either reply with a Signed-off-by?

No, I can't sign a patch that didn't actually pass trough my hands:
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#developer-s-certificate-of-origin-1-1

So in this case this patch is coming from _you_, not me, and there
can't also be a "Signed-off-by: Heikki..." tag.

You can use another tag to tell everybody that the change was
originally proposed by me (I guess it's "Co-developed-by:
Heikki..."?). Or just explain it in the commit message.


thanks,

-- 
heikki