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

From: Mathias Nyman
Date: Fri Aug 30 2019 - 09:38:41 EST

On 26.8.2019 9.41, Ikjoon Jang wrote:
On Wed, Aug 14, 2019 at 9:57 PM Mathias Nyman
<mathias.nyman@xxxxxxxxxxxxxxx> 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