From b9678188b8f570d5c620dd3822485319c38a3709 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 8 Nov 2012 10:17:01 -0500 Subject: [PATCH] USB: EHCI: bugfix: urb->hcpriv should not be NULL 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 Reported-by: Artem S. Tashkinov Reported-by: Christof Meerwald Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: - Adjust context - Also use usb_pipetype() to work out whether we should call qh_put()] Signed-off-by: Ben Hutchings --- drivers/usb/host/ehci-q.c | 16 ++++++---------- drivers/usb/host/ehci-sched.c | 4 ++-- 2 files changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 202373306192..5bb2dcbaa7f9 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -264,18 +264,14 @@ 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--; - } - qh_put (qh); + if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT) { + /* ... update hc-wide periodic stats */ + ehci_to_hcd(ehci)->self.bandwidth_int_reqs--; } + if (usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS) + qh_put((struct ehci_qh *) urb->hcpriv); + if (unlikely(urb->unlinked)) { COUNT(ehci->stats.unlink); } else { diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index a60679cbbf85..34655d0df8d3 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1684,7 +1684,7 @@ itd_link_urb ( /* don't need that schedule data any more */ iso_sched_free (stream, iso_sched); - urb->hcpriv = NULL; + urb->hcpriv = stream; timer_action (ehci, TIMER_IO_WATCHDOG); return enable_periodic(ehci); @@ -2094,7 +2094,7 @@ sitd_link_urb ( /* don't need that schedule data any more */ iso_sched_free (stream, sched); - urb->hcpriv = NULL; + urb->hcpriv = stream; timer_action (ehci, TIMER_IO_WATCHDOG); return enable_periodic(ehci); -- 2.39.2