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

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Message-ID: <65156a02-fe6a-611f-907b-85997ee30755@codeaurora.org>
Date:   Thu, 6 Oct 2016 19:21:33 -0400
From:   Sinan Kaya <okaya@...eaurora.org>
To:     Al Viro <viro@...IV.linux.org.uk>
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, dmaengine <dmaengine@...r.kernel.org>
Subject: Re: [PATCH] Revert "debugfs: ->d_parent is never NULL or negative"

On 10/6/2016 6:41 PM, Al Viro wrote:
> On Thu, Oct 06, 2016 at 11:37:29PM +0100, Al Viro wrote:
> 
>> If you ever get NULL in ->d_parent of struct dentry instance, you are
>> practically certain to have a dangling pointer to memory that used to
>> contain a struct dentry at some point but got freed and reused since then.
> 
> ... which is what happens in your case, apparently.  ->stats is still
> pointing to a dentry that had just been freed and its memory reused.
> 

Thanks for explaining the behavior. I posted the change a minute ago
and forgot to include you. 

dmaengine: qcom_hidma: remove useless debugfs file removal

I have a very similar problem with sysfs now. It looks like the new kernel
is more assertive than the older ones. 

I'll post the sysfs change in a minute. 


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.