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authorAlan Stern <stern@rowland.harvard.edu>2012-11-08 10:17:01 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-11 18:10:45 -0800
commit2656a9abcf1ec8dd5fee6a75d6997a0f2fa0094e (patch)
tree4b16a46e185f001f530c0ba1315371d53d165044 /drivers/usb/host/ehci-sched.c
parent1b36810e27a9791878e4694357ab6d4c06acc22d (diff)
downloadlinux-stericsson-2656a9abcf1ec8dd5fee6a75d6997a0f2fa0094e.tar.gz
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-sched.c')
-rw-r--r--drivers/usb/host/ehci-sched.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 2e14714b359f..69ebee73c0c1 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1630,7 +1630,7 @@ 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);
@@ -2029,7 +2029,7 @@ 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);