[v2.6.34-stable 30/77] staging: usbip: bugfix for deadlock

Paul Gortmaker
2013-01-08T23:37:46Z

From: Bart Westgeest <bart@elbrys.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------

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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/staging/usbip/vhci_rx.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/usbip/vhci_rx.c b/drivers/staging/usbip/vhci_rx.c
index a1ac1b8..b09c67a 100644
--- a/drivers/staging/usbip/vhci_rx.c
+++ b/drivers/staging/usbip/vhci_rx.c
@@ -69,6 +69,7 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev,
{
struct usbip_device *ud = &vdev->ud;
struct urb *urb;
+ unsigned long flags;

spin_lock(&vdev->priv_lock);

@@ -109,9 +110,9 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev,

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);

@@ -152,6 +153,7 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
{
struct vhci_unlink *unlink;
struct urb *urb;
+ unsigned long flags;

usbip_dump_header(pdu);

@@ -183,9 +185,9 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
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);
--
1.7.12.1