From mboxrd@z Thu Jan 1 00:00:00 1970 From: okaya@codeaurora.org (Sinan Kaya) Date: Thu, 6 Oct 2016 19:21:33 -0400 Subject: [PATCH] Revert "debugfs: ->d_parent is never NULL or negative" In-Reply-To: <20161006224117.GP19539@ZenIV.linux.org.uk> References: <1475789429-11414-1-git-send-email-okaya@codeaurora.org> <20161006213734.GM19539@ZenIV.linux.org.uk> <20161006220050.GN19539@ZenIV.linux.org.uk> <20161006223729.GO19539@ZenIV.linux.org.uk> <20161006224117.GP19539@ZenIV.linux.org.uk> Message-ID: <65156a02-fe6a-611f-907b-85997ee30755@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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.