Some usb-serial drivers may access port data in their suspend/
resume functions. Such drivers must always verify the validity
of the data as both suspend and resume can be called both before
usb_serial_device_probe and after usb_serial_device_remove.
But the port data may be invalidated during port_probe and
port_remove. This patch prevents the race against suspend and
resume by disabling suspend while port_probe or port_remove is
running.
Suggested-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
---
drivers/usb/serial/bus.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index f398d1e..c15f2e7 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -61,18 +61,23 @@ static int usb_serial_device_probe(struct device *dev)
goto exit;
}
+ /* make sure suspend/resume doesn't race against port_probe */
+ retval = usb_autopm_get_interface(port->serial->interface);
+ if (retval)
+ goto exit;
+
driver = port->serial->type;
if (driver->port_probe) {
retval = driver->port_probe(port);
if (retval)
- goto exit;
+ goto exit_with_autopm;
}
retval = device_create_file(dev, &dev_attr_port_number);
if (retval) {
if (driver->port_remove)
retval = driver->port_remove(port);
- goto exit;
+ goto exit_with_autopm;
}
minor = port->number;
@@ -81,6 +86,8 @@ static int usb_serial_device_probe(struct device *dev)
"%s converter now attached to ttyUSB%d\n",
driver->description, minor);
+exit_with_autopm:
+ usb_autopm_put_interface(port->serial->interface);
exit:
return retval;
}
@@ -96,6 +103,9 @@ static int usb_serial_device_remove(struct device *dev)
if (!port)
return -ENODEV;
+ /* make sure suspend/resume doesn't race against port_remove */
+ usb_autopm_get_interface(port->serial->interface);
+
device_remove_file(&port->dev, &dev_attr_port_number);
driver = port->serial->type;
@@ -107,6 +117,7 @@ static int usb_serial_device_remove(struct device *dev)
dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
driver->description, minor);
+ usb_autopm_put_interface(port->serial->interface);
return retval;
}
--
1.7.10.4
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