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

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Message-ID: <5883d03d-31c4-206a-26c1-ca641dbf845c@linux.intel.com>
Date:   Wed, 14 Aug 2019 16:59:31 +0300
From:   Mathias Nyman <mathias.nyman@...ux.intel.com>
To:     Ikjoon Jang <ikjn@...omium.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xhci: fix memleak on setup address fails.

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.

-Mathias