This is a note to let you know that I've just added the patch titled
USB: usb_wwan: fix write and suspend race
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 170fad9e22df0063eba0701adb966786d7a4ec5a Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Mon, 26 May 2014 19:23:15 +0200
Subject: 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@xxxxxxxxxxxxxxx> # v2.6.32
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/usb_wwan.c | 13 +++++--------
1 file 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;
--
1.9.0
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