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Subject[12/27] staging: usbip: bugfix for deadlock
2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Bart Westgeest <bart@elbrys.com>

commit 438957f8d4a84daa7fa5be6978ad5897a2e9e5e5 upstream.

Interrupts must be disabled prior to calling usb_hcd_unlink_urb_from_ep.
If interrupts are not disabled, it can potentially lead to a deadlock.
The deadlock is readily reproduceable on a slower (ARM based) device
such as the TI Pandaboard.

Signed-off-by: Bart Westgeest <bart@elbrys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/staging/usbip/vhci_rx.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/staging/usbip/vhci_rx.c
+++ b/drivers/staging/usbip/vhci_rx.c
@@ -67,6 +67,7 @@ static void vhci_recv_ret_submit(struct
{
struct usbip_device *ud = &vdev->ud;
struct urb *urb;
+ unsigned long flags;

spin_lock(&vdev->priv_lock);

@@ -107,9 +108,9 @@ static void vhci_recv_ret_submit(struct

usbip_dbg_vhci_rx("now giveback urb %p\n", urb);

- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);

usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);

@@ -150,6 +151,7 @@ static void vhci_recv_ret_unlink(struct
{
struct vhci_unlink *unlink;
struct urb *urb;
+ unsigned long flags;

usbip_dump_header(pdu);

@@ -181,9 +183,9 @@ static void vhci_recv_ret_unlink(struct
urb->status = pdu->u.ret_unlink.status;
usbip_uinfo("%d\n", urb->status);

- spin_lock(&the_controller->lock);
+ spin_lock_irqsave(&the_controller->lock, flags);
usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
- spin_unlock(&the_controller->lock);
+ spin_unlock_irqrestore(&the_controller->lock, flags);

usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
urb->status);



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