Re: [PATCH] xhci-ring: Fix Null pointer dereference

From: Mathias Nyman
Date: Wed Aug 27 2014 - 10:11:58 EST


On 08/26/2014 06:47 PM, Ricardo Ribalda Delgado wrote:
> While testing a usb gadget I managed to crash completely the host
> computer. This was due to a NULL pointer derefence.
>
> This patch avoids the crash although the kernel still outputs some
> warnings.
>
> Without this patch, kernels from (at least) 3.14 can be crashed with
> mass storage gadgets.
>
> Affected host: NEC Corporation uPD720200 USB 3.0
>


This should not be necessary anymore after
commit 365038d83313951d6ace15342eb24624bbef1666
xhci: rework cycle bit checking for new dequeue pointers

http://marc.info/?l=linux-usb&m=140844993115671&w=2

Which was just added to Greg's usb-linus branch.
It checks that the new_deq_ptr and new_deq_seg are valid before calling
xhci_queue_new_dequeue_state()

-Mathias





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