diff options
| author | Stanislaw Gruszka <sgruszka@redhat.com> | 2014-02-19 10:29:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-26 15:46:42 -0800 |
| commit | a1227f3c1030e96ebc51d677d2f636268845c5fb (patch) | |
| tree | a886ebd7fb7102a20de3a9fca88bee7efc3f8794 /drivers | |
| parent | 6dbd46c849e071e6afc1e0cad489b0175bca9318 (diff) | |
| download | linux-a1227f3c1030e96ebc51d677d2f636268845c5fb.tar.bz2 | |
usb: ehci: fix deadlock when threadirqs option is used
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 <sgruszka@redhat.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 471142725ffe..81cda09b47e3 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -685,8 +685,15 @@ 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); @@ -704,7 +711,7 @@ 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; } @@ -815,7 +822,7 @@ 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; |