From: Andrea Righi <arighi@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/usb/core/hcd.c | 5 +++++
drivers/usb/host/ehci-hcd.c | 3 ++-
2 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 0358c05..c5753c7 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1218,6 +1218,11 @@ static int hcd_alloc_coherent(struct usb_bus *bus,
{
unsigned char *vaddr;
+ if (*vaddr_handle == NULL) {
+ WARN_ON_ONCE(1);
+ return -EFAULT;
+ }
+
vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
mem_flags, dma_handle);
if (!vaddr)
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 @@ static int ehci_init(struct usb_hcd *hcd)
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;
}
--
1.7.2
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
