3.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alan Stern <[email protected]> commit 2656a9abcf1ec8dd5fee6a75d6997a0f2fa0094e upstream. 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 <[email protected]> Reported-by: Artem S. Tashkinov <[email protected]> Reported-by: Christof Meerwald <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/usb/host/ehci-q.c | 12 +++--------- drivers/usb/host/ehci-sched.c | 4 ++-- 2 files changed, 5 insertions(+), 11 deletions(-) --- 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, 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)) { --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1646,7 +1646,7 @@ 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); @@ -2045,7 +2045,7 @@ 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
