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USB: OHCI: Don't mark EDs as ED_OPER if scheduling fails

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commit c66f59ee50 upstream.

Since ed_schedule begins with marking the ED as "operational",
the ED may be left in such state even if scheduling actually
fails.

This allows future submission attempts to smuggle this ED to the
hardware behind the scheduler's back and without linking it to
the ohci->eds_in_use list.

The former causes bandwidth saturation and data loss on isoc
endpoints, the latter crashes the kernel when attempt is made
to unlink such ED from this list.

Fix ed_schedule to update ED state only on successful return.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michał Pecio 2016-06-07 12:34:45 +02:00 committed by Greg Kroah-Hartman
parent b05965f284
commit 2053f7db7a
1 changed files with 2 additions and 1 deletions
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3
drivers/usb/host/ohci-q.c
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@ -183,7 +183,6 @@ static int ed_schedule (struct ohci_hcd *ohci, struct ed *ed)
{
int branch;
ed->state = ED_OPER;
ed->ed_prev = NULL;
ed->ed_next = NULL;
ed->hwNextED = 0;
@ -259,6 +258,8 @@ static int ed_schedule (struct ohci_hcd *ohci, struct ed *ed)
/* the HC may not see the schedule updates yet, but if it does
* then they'll be properly ordered.
*/
ed->state = ED_OPER;
return 0;
}