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authorAlan Stern <stern@rowland.harvard.edu>2012-11-08 19:17:01 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-12 06:10:45 +0400
commit2656a9abcf1ec8dd5fee6a75d6997a0f2fa0094e (patch)
tree4b16a46e185f001f530c0ba1315371d53d165044 /drivers/usb/host/ehci-q.c
parent1b36810e27a9791878e4694357ab6d4c06acc22d (diff)
downloadlinux-2656a9abcf1ec8dd5fee6a75d6997a0f2fa0094e.tar.xz
USB: EHCI: bugfix: urb->hcpriv should not be NULL
This patch (as1632b) fixes a bug in ehci-hcd. The USB core uses urb->hcpriv to determine whether or not an URB is active; host controller drivers are supposed to set this pointer to a non-NULL value when an URB is queued. However ehci-hcd sets it to NULL for isochronous URBs, which defeats the check in usbcore. In itself this isn't a big deal. But people have recently found that certain sequences of actions will cause the snd-usb-audio driver to reuse URBs without waiting for them to complete. In the absence of proper checking by usbcore, the URBs get added to their endpoint list twice. This leads to list corruption and a system freeze. The patch makes ehci-hcd assign a meaningful value to urb->hcpriv for isochronous URBs. Improving robustness always helps. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Artem S. Tashkinov <t.artem@lycos.com> Reported-by: Christof Meerwald <cmeerw@cmeerw.org> CC: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
-rw-r--r--drivers/usb/host/ehci-q.c12
1 files changed, 3 insertions, 9 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 4b66374bdc8e..3d989028c836 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -264,15 +264,9 @@ ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
__releases(ehci->lock)
__acquires(ehci->lock)
{
- if (likely (urb->hcpriv != NULL)) {
- struct ehci_qh *qh = (struct ehci_qh *) urb->hcpriv;
-
- /* S-mask in a QH means it's an interrupt urb */
- if ((qh->hw->hw_info2 & cpu_to_hc32(ehci, QH_SMASK)) != 0) {
-
- /* ... update hc-wide periodic stats (for usbfs) */
- ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
- }
+ if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) {
+ /* ... update hc-wide periodic stats */
+ ehci_to_hcd(ehci)->self.bandwidth_int_reqs--;
}
if (unlikely(urb->unlinked)) {