linux-kernel - Re: [PATCH] Revert "debugfs: ->d_parent is never NULL or negative"

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Message-ID: <20161006220050.GN19539@ZenIV.linux.org.uk>
Date:   Thu, 6 Oct 2016 23:00:51 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Sinan Kaya <okaya@...eaurora.org>
Cc:     timur@...eaurora.org, cov@...eaurora.org,
        linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "debugfs: ->d_parent is never NULL or negative"

On Thu, Oct 06, 2016 at 05:41:34PM -0400, Sinan Kaya wrote:
> On 10/6/2016 5:37 PM, Al Viro wrote:
> > On Thu, Oct 06, 2016 at 05:30:29PM -0400, Sinan Kaya wrote:
> >> This reverts commit acc29fb8f792 ("debugfs: ->d_parent is never NULL or
> >> negative") as it breaks the debugfs_remove_recursive API as show in the
> >> callstack below.
> > 
> > NAK.  Fix your code, don't break global asserts.
> > 
> 
> I can fix the code if you tell me what the problem is:

Getting dentries with NULL ->d_parent should never, ever happen.  Find the
place where such a beast appears and you've got your problem.

The same goes for negative dentries with children.  Again, if your code
triggers such a situation, find where it does so and you've found a bug.
More than one, at that.