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authorJohan Hovold <jhovold@gmail.com>2014-05-26 19:23:15 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-27 15:04:05 -0700
commit170fad9e22df0063eba0701adb966786d7a4ec5a (patch)
tree3437346642f8e76f5c39298106e576a0f7c8dfa6 /drivers/usb/serial
parentd9e93c08d8d985e5ef89436ebc9f4aad7e31559f (diff)
USB: usb_wwan: fix write and suspend race
Fix race between write() and suspend() which could lead to writes being dropped (or I/O while suspended) if the device is runtime suspended while a write request is being processed. Specifically, suspend() releases the susp_lock after determining the device is idle but before setting the suspended flag, thus leaving a window where a concurrent write() can submit an urb. Fixes: 383cedc3bb43 ("USB: serial: full autosuspend support for the option driver") Cc: <stable@vger.kernel.org> # v2.6.32 Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial')
-rw-r--r--drivers/usb/serial/usb_wwan.c13
1 files changed, 5 insertions, 8 deletions
diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
index 112693a4100b..2b8f02696c00 100644
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -579,20 +579,17 @@ static void stop_read_write_urbs(struct usb_serial *serial)
int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message)
{
struct usb_wwan_intf_private *intfdata = serial->private;
- int b;
+ spin_lock_irq(&intfdata->susp_lock);
if (PMSG_IS_AUTO(message)) {
- spin_lock_irq(&intfdata->susp_lock);
- b = intfdata->in_flight;
- spin_unlock_irq(&intfdata->susp_lock);
-
- if (b)
+ if (intfdata->in_flight) {
+ spin_unlock_irq(&intfdata->susp_lock);
return -EBUSY;
+ }
}
-
- spin_lock_irq(&intfdata->susp_lock);
intfdata->suspended = 1;
spin_unlock_irq(&intfdata->susp_lock);
+
stop_read_write_urbs(serial);
return 0;