From 170fad9e22df0063eba0701adb966786d7a4ec5a Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 26 May 2014 19:23:15 +0200 Subject: [PATCH] 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: # v2.6.32 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/usb_wwan.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 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; - - if (PMSG_IS_AUTO(message)) { - spin_lock_irq(&intfdata->susp_lock); - b = intfdata->in_flight; - spin_unlock_irq(&intfdata->susp_lock); - - if (b) - return -EBUSY; - } spin_lock_irq(&intfdata->susp_lock); + if (PMSG_IS_AUTO(message)) { + if (intfdata->in_flight) { + spin_unlock_irq(&intfdata->susp_lock); + return -EBUSY; + } + } intfdata->suspended = 1; spin_unlock_irq(&intfdata->susp_lock); + stop_read_write_urbs(serial); return 0;