linux-kernel - Re: [PATCH] xhci: fix memleak on setup address fails.

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Date:   Fri, 30 Aug 2019 16:40:25 +0300
From:   Mathias Nyman <mathias.nyman@...ux.intel.com>
To:     Ikjoon Jang <ikjn@...omium.org>
Cc:     Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xhci: fix memleak on setup address fails.

On 26.8.2019 9.41, Ikjoon Jang wrote:
> On Wed, Aug 14, 2019 at 9:57 PM Mathias Nyman
> <mathias.nyman@...ux.intel.com> wrote:
>>
>> On 11.8.2019 11.22, Ikjoon Jang wrote:
>>> Xhci re-enables a slot on transaction error in set_address using
>>> xhci_disable_slot() + xhci_alloc_dev().
>>>
>>> But in this case, xhci_alloc_dev() creates debugfs entries upon an
>>> existing device without cleaning up old entries, thus memory leaks.
>>>
>>> So this patch simply moves calling xhci_debugfs_free_dev() from
>>> xhci_free_dev() to xhci_disable_slot().
>>>
>>
>> Othwerwise this looks good, but xhci_alloc_dev() will call xhci_disable_slot()
>> in some failure cases before the slot debugfs entry is created.
>>
>> In these cases xhci_debugfs_remove_slot() will be called without
>> xhci_debugfs_create_slot() ever being called.
>>
>> This might not be an issue as xhci_debugfs_remove_slot() checks
>> if (!dev || !dev->debugfs_private) before doing anything, but should
>> be checked out.
>>
> 
> I checked out the case by adding simple fault injection on xhci_alloc_dev(),
> to simulate xhci_debugfs_remove_slot() can be called without
> xhci_debugfs_create_slot() being called.
> 

Thanks, patch sent forward

-Mathias