diff options
Diffstat (limited to 'usb-ehci-fix-deadlock-when-threadirqs-option-is-used.patch')
| -rw-r--r-- | usb-ehci-fix-deadlock-when-threadirqs-option-is-used.patch | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/usb-ehci-fix-deadlock-when-threadirqs-option-is-used.patch b/usb-ehci-fix-deadlock-when-threadirqs-option-is-used.patch new file mode 100644 index 000000000..9593c14e2 --- /dev/null +++ b/usb-ehci-fix-deadlock-when-threadirqs-option-is-used.patch @@ -0,0 +1,57 @@ +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> +--- + 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 4711427..0bc6410 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; +-- +1.7.11.7 + +-- +To unsubscribe from this list: send the line "unsubscribe linux-usb" in +the body of a message to majordomo@vger.kernel.org +More majordomo info at http://vger.kernel.org/majordomo-info.html
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