3.11.10.6 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Stanislaw Gruszka <[email protected]> commit a1227f3c1030e96ebc51d677d2f636268845c5fb upstream. ehci_irq() and ehci_hrtimer_func() can deadlock on ehci->lock when threadirqs option is used. To prevent the deadlock use spin_lock_irqsave() in ehci_irq(). This change can be reverted when hrtimer callbacks become threaded. Signed-off-by: Stanislaw Gruszka <[email protected]> Acked-by: Alan Stern <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Luis Henriques <[email protected]> --- drivers/usb/host/ehci-hcd.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 7abf1ce..9a91bb6 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -689,8 +689,15 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) struct ehci_hcd *ehci = hcd_to_ehci (hcd); u32 status, masked_status, pcd_status = 0, cmd; int bh; + unsigned long flags; - spin_lock (&ehci->lock); + /* + * For threadirqs option we use spin_lock_irqsave() variant to prevent + * deadlock with ehci hrtimer callback, because hrtimer callbacks run + * in interrupt context even when threadirqs is specified. We can go + * back to spin_lock() variant when hrtimer callbacks become threaded. + */ + spin_lock_irqsave(&ehci->lock, flags); status = ehci_readl(ehci, &ehci->regs->status); @@ -708,7 +715,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* Shared IRQ? */ if (!masked_status || unlikely(ehci->rh_state == EHCI_RH_HALTED)) { - spin_unlock(&ehci->lock); + spin_unlock_irqrestore(&ehci->lock, flags); return IRQ_NONE; } @@ -826,7 +833,7 @@ dead: if (bh) ehci_work (ehci); - spin_unlock (&ehci->lock); + spin_unlock_irqrestore(&ehci->lock, flags); if (pcd_status) usb_hcd_poll_rh_status(hcd); return IRQ_HANDLED; -- 1.9.0 -- 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/
