From: Pete Zaitcev Date: Mon, 2 Jun 2008 04:23:07 +0000 (-0700) Subject: USB: ohci_hcd hang: submit vs. rmmod race X-Git-Tag: v2.6.27-rc1~946^2~45 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=6deb270b5c60680ca9117bd545302ea6a58bad42;p=linux-2.6-omap-h63xx.git USB: ohci_hcd hang: submit vs. rmmod race If we do rmmod ohci_hcd while an application is doing something, the following may happen: - a control URB completes (in finish_urb) and the ohci's endpoint is set into ED_UNLINK in ed_deschedule - same URB is (re)submitted because of the open/close loop or other such application behaviour - rmmod sets the state to HC_STATE_QUESCING - finish_unlinks happens at next SOF; normally it would set ed into ED_IDLE and immediately call ed_schedule (since URB had extra TDs queued), which sets it into ED_OPER. But the check in ed_schedule makes it fail with -EAGAIN (which is ignored) - from now on we have a dead URB stuck; it cannot even be unlinked because the ed status is not ED_OPER, and thus start_ed_unlink is not invoked. This patch removes the check. In 2.6.25, all callers check for __ACTIVE bit before invoking ed_schedule, which is more appropriate. Alan Stern and David Brownell approved of this (cautiously). Signed-off-by: Pete Zaitcev Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c index 9b547407c93..6a9b4c55795 100644 --- a/drivers/usb/host/ohci-q.c +++ b/drivers/usb/host/ohci-q.c @@ -159,9 +159,6 @@ static int ed_schedule (struct ohci_hcd *ohci, struct ed *ed) { int branch; - if (ohci_to_hcd(ohci)->state == HC_STATE_QUIESCING) - return -EAGAIN; - ed->state = ED_OPER; ed->ed_prev = NULL; ed->ed_next = NULL;