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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: 383cedc3bb
("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>
This commit is contained in:
parent
d9e93c08d8
commit
170fad9e22
1 changed files with 7 additions and 10 deletions
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@ -579,20 +579,17 @@ static void stop_read_write_urbs(struct usb_serial *serial)
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int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message)
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{
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struct usb_wwan_intf_private *intfdata = serial->private;
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int b;
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if (PMSG_IS_AUTO(message)) {
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spin_lock_irq(&intfdata->susp_lock);
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b = intfdata->in_flight;
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spin_unlock_irq(&intfdata->susp_lock);
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if (b)
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return -EBUSY;
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}
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spin_lock_irq(&intfdata->susp_lock);
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if (PMSG_IS_AUTO(message)) {
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if (intfdata->in_flight) {
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spin_unlock_irq(&intfdata->susp_lock);
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return -EBUSY;
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}
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}
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intfdata->suspended = 1;
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spin_unlock_irq(&intfdata->susp_lock);
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stop_read_write_urbs(serial);
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return 0;
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