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From tom.leiming@gmail.com Thu Aug 12 13:50:12 2010
From: tom.leiming@gmail.com
To: greg@kroah.com,
stern@rowland.harvard.edu
Cc: linux-usb@vger.kernel.org, Ming Lei <tom.leiming@gmail.com>, Johan Hovold <jhovold@gmail.com>, Andi Kleen <ak@linux.intel.com>
Subject: USB: serial: fix leak of usb serial module refrence count
Date: Sat, 7 Aug 2010 16:20:35 +0800
Message-Id: <1281169235-4883-1-git-send-email-tom.leiming@gmail.com>
From: Ming Lei <tom.leiming@gmail.com>
The patch with title below makes reference count of usb serial module
always more than one after driver is bound.
USB-BKL: Remove BKL use for usb serial driver probing
In fact, the patch above only replaces lock_kernel() with try_module_get()
, and does not use module_put() to do what unlock_kernel() did, so casue leak
of reference count of usb serial module and the module can not be unloaded
after serial driver is bound with device.
This patch fixes the issue, also simplifies such things:
-only call try_module_get() once in the entry of usb_serial_probe()
-only call module_put() once in the exit of usb_serial_probe
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/usb/serial/usb-serial.c | 23 +++++++----------------
1 file changed, 7 insertions(+), 16 deletions(-)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -736,6 +736,7 @@ int usb_serial_probe(struct usb_interfac
serial = create_serial(dev, interface, type);
if (!serial) {
+ module_put(type->driver.owner);
dev_err(&interface->dev, "%s - out of memory\n", __func__);
return -ENOMEM;
}
@@ -746,11 +747,11 @@ int usb_serial_probe(struct usb_interfac
id = get_iface_id(type, interface);
retval = type->probe(serial, id);
- module_put(type->driver.owner);
if (retval) {
dbg("sub driver rejected device");
kfree(serial);
+ module_put(type->driver.owner);
return retval;
}
}
@@ -822,6 +823,7 @@ int usb_serial_probe(struct usb_interfac
if (num_bulk_in == 0 || num_bulk_out == 0) {
dev_info(&interface->dev, "PL-2303 hack: descriptors matched but endpoints did not\n");
kfree(serial);
+ module_put(type->driver.owner);
return -ENODEV;
}
}
@@ -835,22 +837,15 @@ int usb_serial_probe(struct usb_interfac
dev_err(&interface->dev,
"Generic device with no bulk out, not allowed.\n");
kfree(serial);
+ module_put(type->driver.owner);
return -EIO;
}
}
#endif
if (!num_ports) {
/* if this device type has a calc_num_ports function, call it */
- if (type->calc_num_ports) {
- if (!try_module_get(type->driver.owner)) {
- dev_err(&interface->dev,
- "module get failed, exiting\n");
- kfree(serial);
- return -EIO;
- }
+ if (type->calc_num_ports)
num_ports = type->calc_num_ports(serial);
- module_put(type->driver.owner);
- }
if (!num_ports)
num_ports = type->num_ports;
}
@@ -1039,13 +1034,7 @@ int usb_serial_probe(struct usb_interfac
/* if this device type has an attach function, call it */
if (type->attach) {
- if (!try_module_get(type->driver.owner)) {
- dev_err(&interface->dev,
- "module get failed, exiting\n");
- goto probe_error;
- }
retval = type->attach(serial);
- module_put(type->driver.owner);
if (retval < 0)
goto probe_error;
serial->attached = 1;
@@ -1088,10 +1077,12 @@ int usb_serial_probe(struct usb_interfac
exit:
/* success */
usb_set_intfdata(interface, serial);
+ module_put(type->driver.owner);
return 0;
probe_error:
usb_serial_put(serial);
+ module_put(type->driver.owner);
return -EIO;
}
EXPORT_SYMBOL_GPL(usb_serial_probe);
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