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@xxxxxxxxxxxxxxxxxxx>
Reported-by: Artem S. Tashkinov <t.artem@xxxxxxxxx>
Reported-by: Christof Meerwald <cmeerw@xxxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
---
v.2: Restore hunk from ehci-q.c which was accidentally truncated from
the original patch submission.
Patch 2/2 in this series remains the same, no update.
drivers/usb/host/ehci-q.c | 12 +++---------
drivers/usb/host/ehci-sched.c | 4 ++--
2 files changed, 5 insertions(+), 11 deletions(-)
Index: usb-3.7/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-3.7.orig/drivers/usb/host/ehci-sched.c
+++ usb-3.7/drivers/usb/host/ehci-sched.c
@@ -1632,7 +1632,7 @@ static void itd_link_urb(
/* don't need that schedule data any more */
iso_sched_free (stream, iso_sched);
- urb->hcpriv = NULL;
+ urb->hcpriv = stream;
++ehci->isoc_count;
enable_periodic(ehci);
@@ -2031,7 +2031,7 @@ static void sitd_link_urb(
/* don't need that schedule data any more */
iso_sched_free (stream, sched);
- urb->hcpriv = NULL;
+ urb->hcpriv = stream;
++ehci->isoc_count;
enable_periodic(ehci);
Index: usb-3.7/drivers/usb/host/ehci-q.c
===================================================================
--- usb-3.7.orig/drivers/usb/host/ehci-q.c
+++ usb-3.7/drivers/usb/host/ehci-q.c
@@ -264,15 +264,9 @@ ehci_urb_done(struct ehci_hcd *ehci, str
__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)) {
--
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