From: Andrea Righi <arighi@develer.com>
Date: Mon, 28 Jun 2010 14:56:45 +0000 (+0200)
Subject: USB: EHCI: fix NULL pointer dererence in HCDs that use HCD_LOCAL_MEM
X-Git-Tag: v2.6.36-rc1~293^2~88
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4307a28eb0128417d9a2b9d858d2bce70ee5b383;p=pandora-kernel.git

USB: EHCI: fix NULL pointer dererence in HCDs that use HCD_LOCAL_MEM

If we use the HCD_LOCAL_MEM flag and dma_declare_coherent_memory() to
enforce the host controller's local memory utilization we also need to
disable native scatter-gather support, otherwise hcd_alloc_coherent() in
map_urb_for_dma() is called with urb->transfer_buffer == NULL, that
triggers a NULL pointer dereference.

We can also consider to add a WARN_ON() and return an error code to
better catch this problem in the future.

At the moment no driver seems to hit this bug, so I should
consider this a low-priority fix.

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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