From 779d516ca91d796cb37bd0760282d08f90661ee2 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Sun, 23 Dec 2012 21:09:55 +0100 Subject: [PATCH] usb: gadget: composite: don't call driver's unbind() if bind() failed Lets assume nokia_bind() starts with "return -EINVAL". After loading the gadget we end up with: |udc dummy_udc.0: registering UDC driver [g_nokia] |BUG: unable to handle kernel NULL pointer dereference at 00000040 |IP: [] __list_add+0x25/0xf0 |Call Trace: | [] rollback_registered+0x21/0x40 | [] unregister_netdevice_queue+0x4f/0xa0 | [] unregister_netdev+0x19/0x30 | [] gphonet_cleanup+0x32/0x50 [g_nokia] | [] nokia_unbind+0x1c/0x2a [g_nokia] | [] __composite_unbind.constprop.10+0x4f/0xb0 [libcomposite] | [] composite_bind+0x1ae/0x230 [libcomposite] | [] usb_gadget_probe_driver+0xc6/0x1b0 | [] usb_composite_probe+0x7a/0xa0 [libcomposite] That is crash from nokia_unbind() invoked via nokia_bind(). This crash will look different we if make it until usb_string_ids_tab() before we enter an error condition in the probe function. nokia_bind_config() tries to clean up which is IMHO the right thing to do. Leaving things as-is and hoping that its unbind() will clean it up is kinda backwards. Especially since the bind function never succeeded so it can't know how much it needs to clean up. This fixes the behaviour by not calling the driver's unbind function if its bind function failed. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Felipe Balbi --- drivers/usb/gadget/composite.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index 71475b6d8568..9db000013f5d 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -1349,8 +1349,7 @@ static ssize_t composite_show_suspended(struct device *dev, static DEVICE_ATTR(suspended, 0444, composite_show_suspended, NULL); -static void -composite_unbind(struct usb_gadget *gadget) +static void __composite_unbind(struct usb_gadget *gadget, bool unbind_driver) { struct usb_composite_dev *cdev = get_gadget_data(gadget); @@ -1367,7 +1366,7 @@ composite_unbind(struct usb_gadget *gadget) struct usb_configuration, list); remove_config(cdev, c); } - if (cdev->driver->unbind) + if (cdev->driver->unbind && unbind_driver) cdev->driver->unbind(cdev); if (cdev->req) { @@ -1380,6 +1379,11 @@ composite_unbind(struct usb_gadget *gadget) set_gadget_data(gadget, NULL); } +static void composite_unbind(struct usb_gadget *gadget) +{ + __composite_unbind(gadget, true); +} + static void update_unchanged_dev_desc(struct usb_device_descriptor *new, const struct usb_device_descriptor *old) { @@ -1488,7 +1492,7 @@ static int composite_bind(struct usb_gadget *gadget, return 0; fail: - composite_unbind(gadget); + __composite_unbind(gadget, false); return status; } -- 2.30.2