[PATCH] USB: ehci: fix bogus alteration of a local variable

In a rare and all-but-unused path, the EHCI driver could reuse a variable
in a way that'd make trouble.  Specifically, if the first root hub port
gets an overcurrent event (rare) during a remote wakeup scenario (all but
unused in today's Linux, except for folk working with suspend-to-RAM and
similar sleep states), that would look like a fatal error which would shut
down the controller.  Fix by not reusing that variable.

Spotted by Per Hallsmark <saxofon@musiker.nu>
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6661

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index cee6f53..85b0b4a 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -625,10 +625,11 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd, struct pt_regs *regs)
                        writel (status | CMD_RUN, &ehci->regs->command);
 
                while (i--) {
-                       status = readl (&ehci->regs->port_status [i]);
-                       if (status & PORT_OWNER)
+                       int pstatus = readl (&ehci->regs->port_status [i]);
+
+                       if (pstatus & PORT_OWNER)
                                continue;
-                       if (!(status & PORT_RESUME)
+                       if (!(pstatus & PORT_RESUME)
                                        || ehci->reset_done [i] != 0)
                                continue;