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>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 2a19336..2e704fa 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -629,7 +629,8 @@
ehci->command = temp;
/* Accept arbitrarily long scatter-gather lists */
- hcd->self.sg_tablesize = ~0;
+ if (!(hcd->driver->flags & HCD_LOCAL_MEM))
+ hcd->self.sg_tablesize = ~0;
return 0;
}