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.
Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx>
---
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 12742f1..161c757 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1219,6 +1219,11 @@ 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 a3ef2a9..27e0351 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -606,7 +606,8 @@ 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;
}
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